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Dig Or Die=I Die
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2,022 Posts
Discussion Starter · #1 ·
Patient is a 1998 2dr 2wd 4.3/auto GMC Jimmy w/Wynjammer S/[email protected], marine intake, 42lb/hr injectors and a 255 walbro in-tank fuel pump.

This is for any of you guys out there that has done the Marine Intake swap, the 2114 MPI swap or/and the 255 Walbro swap. Have any of you guys noticed hard cold starts?

Seems ever since I've had the MI installed, the Jimmy is hard to start in the morning and after I get off work.

When the truck is warm it'll fir right up. It's all most always hard to start when it's cold. The Jimmy never had the problem until after the marine intake was installed.

If you've done the MI/2114 swap have you also done the walbro? When you did the walbro did you just got the whole module or did you remove the brass fitting from the stock pump, press it in the walbro and keep the plunger thing and reconnect that little hose?

If I turn the key and hold it right at the point before it will turn the engine over the pump will run longer and I think it lets more fuel spray in the chambers. When I do that it'll fire right up most the time.

So I was thinking it might have to do with how much fuel or how long the injectors spray fuel at start up. So I suspect it's something in the tune.

Then it could also be a problem with the pump or how I installed it. I have checked the fuel pressure many times in the past and it was good. Although I haven't checked it recently. I'll get around to putting a gauge on it tomorrow. Pump is new. Fuel filter is probably not much more then 6 months old and I had the tank dropped not long ago and it's spotless.

If it's not a pump or other mechanical issue, then what table(s) in my tune should I look at?

Could it have something to do with injector controls, cranking fuel? How about Injector Timing?


EDIT:

I just went out to the truck and put the gauge on it now. All's normal.

NOTE for non-Marine intake guys: Keep in mind that the marine intake is different then the stock system. The test port is after the FPR.

FP sits right at about 48-50, engine off/key on. When the pump primes it jumps right up to 58-60. Then goes right back down to 48-50 when the pump stops. Cranking I get 58-60, running it's steady at 48-50. Hit the throttle and it goes right up to 58-60 like it should and drops right back to 48-50. Never drops below. So FP is right on.

I'll walk out there in a bit and see if it blends down much. When I hooked up the FPG (fuel pressure gauge) there was no FP at all at the port. But the FPR is before the test port so I believe that is normal.

So it's got to be something in the tune that'll fix it. Right? Or could I be wrong?
 

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WICKED 6 RACING
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2,189 Posts
Try hot wiring the pump. Make it so the pump constantly runs. If it solves the problem, then more then like the prime cycle will need to be extended. If on the other hand it does nothing its more in like in the cold part of the tune or a sensor. Never dealt with the marine intake or its setup. But have played with lots of V8 Tune port setups. And the test port is always after or directly in the regulator but before the fuel rail. And even some of them are finicky in the cold weather on primary start up with the blowers installed.
 

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Addicted to boost
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767 Posts
As you pry already now I have a similiar setup. When I installed the pumpI got just thepump and I ended up epoxing the brass fitting in if I remember correctly. I had a similiar problem to yours originally. I wasn't happy with how long it cranked for when cold but it would fire right off hot. I believe most of the changes I made where in the Startup idle air which I increased and cranking fuel below 100*. I know that its hard to view my tune cause I'm using the beta version of HP, Ill try and check which tables I changed and upload some info for you.
 

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Addicted to boost
Joined
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767 Posts
Heres idle airflow verse coolant temp

2.1058 2.0964 2.0870 1.9015 1.7098 1.4498 1.2260 1.0282 0.8428 0.7455 0.7150 0.7150 0.7150 0.7606 0.7757 0.7757

Heres openloop f/a vs coolant temp vs map

1.360 1.235 1.125 1.081 1.030 1.010 1.010 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.361 1.245 1.136 1.081 1.040 1.011 1.015 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.361 1.300 1.230 1.092 1.051 1.021 1.010 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.410 1.360 1.261 1.101 1.046 1.030 1.021 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.430 1.370 1.280 1.111 1.061 1.040 1.021 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.430 1.370 1.280 1.121 1.070 1.041 1.030 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.430 1.390 1.291 1.131 1.081 1.051 1.040 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.430 1.390 1.301 1.136 1.095 1.061 1.055 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.440 1.400 1.311 1.171 1.110 1.070 1.053 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.440 1.400 1.311 1.166 1.121 1.081 1.056 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.440 1.400 1.311 1.171 1.131 1.091 1.060 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.440 1.400 1.320 1.171 1.126 1.110 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.470 1.430 1.341 1.211 1.141 1.134 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.470 1.430 1.351 1.206 1.150 1.143 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.470 1.430 1.351 1.221 1.160 1.150 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.470 1.430 1.351 1.230 1.171 1.149 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.470 1.430 1.351 1.230 1.181 1.147 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000


This is the 400 and 600 columns on my high octane spark table

34.0 35.6
29.8 32.1
25.9 28.5
21.9 24.9
17.9 21.3
14.0 17.8
11.0 15.1
8.2 12.6
5.4 10.0
2.5 7.2
-0.1 4.6
-2.2 2.4
-3.8 0.1
-4.1 -0.5
-4.4 -0.9
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3

I forgot to mention the reduced timing in these columns

Transient fueling impact factor vs coolant vs map

0.3452 0.3164 0.2852 0.2549 0.2314 0.2153 0.1992 0.1836 0.1670 0.1504 0.1333 0.1167 0.1001 0.0835 0.0669 0.0601 0.0601 0.0586 0.0498
0.4141 0.3921 0.3687 0.3438 0.3213 0.3032 0.2832 0.2656 0.2397 0.2148 0.1899 0.1650 0.1401 0.1235 0.1069 0.0928 0.0815 0.0708 0.0498
0.4824 0.4678 0.4521 0.4326 0.4111 0.3911 0.3672 0.3481 0.3130 0.2798 0.2466 0.2134 0.1802 0.1636 0.1470 0.1250 0.1030 0.0830 0.0498
0.5063 0.4922 0.4775 0.4580 0.4360 0.4150 0.3921 0.3735 0.3384 0.3022 0.2666 0.2334 0.2002 0.1753 0.1567 0.1353 0.1113 0.0884 0.0552
0.5303 0.5166 0.5020 0.4834 0.4609 0.4385 0.4165 0.3984 0.3633 0.3247 0.2866 0.2534 0.2202 0.1870 0.1670 0.1450 0.1201 0.0933 0.0601
0.5464 0.5317 0.5176 0.4980 0.4741 0.4497 0.4268 0.4082 0.3701 0.3325 0.2964 0.2632 0.2305 0.1968 0.1768 0.1553 0.1299 0.1035 0.0703
0.5625 0.5479 0.5322 0.5127 0.4873 0.4609 0.4375 0.4185 0.3765 0.3398 0.3066 0.2729 0.2402 0.2070 0.1870 0.1650 0.1401 0.1133 0.0801
0.5713 0.5552 0.5391 0.5176 0.4912 0.4639 0.4419 0.4194 0.3765 0.3398 0.3066 0.2729 0.2402 0.2070 0.1870 0.1675 0.1450 0.1182 0.0850
0.5801 0.5625 0.5449 0.5225 0.4951 0.4673 0.4458 0.4199 0.3765 0.3398 0.3066 0.2729 0.2402 0.2070 0.1870 0.1699 0.1499 0.1230 0.0898


Transient impact factor vs gain

1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.7759
1.7017
1.6279
1.5430
1.4688
1.3877
1.2954
1.2021
1.1284
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361

Hope this is more helpful than confusing.
 

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Dig Or Die=I Die
Joined
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2,022 Posts
Discussion Starter · #5 ·
As you pry already now I have a similiar setup. When I installed the pumpI got just thepump and I ended up epoxing the brass fitting in if I remember correctly. I had a similiar problem to yours originally. I wasn't happy with how long it cranked for when cold but it would fire right off hot. I believe most of the changes I made where in the Startup idle air which I increased and cranking fuel below 100*. I know that its hard to view my tune cause I'm using the beta version of HP, Ill try and check which tables I changed and upload some info for you.
You could just name the areas you changed. No since in going though all that trouble since I have the 98 PCM and things or going to be different. So either way I'm going to have to improvise and figure it out.

Here's an example of what I'm talking about when i say "different" This is a screen shot of my Fuel Control Tables.

 

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Dig Or Die=I Die
Joined
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2,022 Posts
Discussion Starter · #6 ·
Heres idle airflow verse coolant temp

2.1058 2.0964 2.0870 1.9015 1.7098 1.4498 1.2260 1.0282 0.8428 0.7455 0.7150 0.7150 0.7150 0.7606 0.7757 0.7757

Heres openloop f/a vs coolant temp vs map

1.360 1.235 1.125 1.081 1.030 1.010 1.010 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.361 1.245 1.136 1.081 1.040 1.011 1.015 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.361 1.300 1.230 1.092 1.051 1.021 1.010 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.410 1.360 1.261 1.101 1.046 1.030 1.021 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.430 1.370 1.280 1.111 1.061 1.040 1.021 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.430 1.370 1.280 1.121 1.070 1.041 1.030 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.430 1.390 1.291 1.131 1.081 1.051 1.040 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.430 1.390 1.301 1.136 1.095 1.061 1.055 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.440 1.400 1.311 1.171 1.110 1.070 1.053 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.440 1.400 1.311 1.166 1.121 1.081 1.056 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.440 1.400 1.311 1.171 1.131 1.091 1.060 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.440 1.400 1.320 1.171 1.126 1.110 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.470 1.430 1.341 1.211 1.141 1.134 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.470 1.430 1.351 1.206 1.150 1.143 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.470 1.430 1.351 1.221 1.160 1.150 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.470 1.430 1.351 1.230 1.171 1.149 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
1.470 1.430 1.351 1.230 1.181 1.147 1.070 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000


This is the 400 and 600 columns on my high octane spark table

34.0 35.6
29.8 32.1
25.9 28.5
21.9 24.9
17.9 21.3
14.0 17.8
11.0 15.1
8.2 12.6
5.4 10.0
2.5 7.2
-0.1 4.6
-2.2 2.4
-3.8 0.1
-4.1 -0.5
-4.4 -0.9
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3
-4.9 -2.3

I forgot to mention the reduced timing in these columns

Transient fueling impact factor vs coolant vs map

0.3452 0.3164 0.2852 0.2549 0.2314 0.2153 0.1992 0.1836 0.1670 0.1504 0.1333 0.1167 0.1001 0.0835 0.0669 0.0601 0.0601 0.0586 0.0498
0.4141 0.3921 0.3687 0.3438 0.3213 0.3032 0.2832 0.2656 0.2397 0.2148 0.1899 0.1650 0.1401 0.1235 0.1069 0.0928 0.0815 0.0708 0.0498
0.4824 0.4678 0.4521 0.4326 0.4111 0.3911 0.3672 0.3481 0.3130 0.2798 0.2466 0.2134 0.1802 0.1636 0.1470 0.1250 0.1030 0.0830 0.0498
0.5063 0.4922 0.4775 0.4580 0.4360 0.4150 0.3921 0.3735 0.3384 0.3022 0.2666 0.2334 0.2002 0.1753 0.1567 0.1353 0.1113 0.0884 0.0552
0.5303 0.5166 0.5020 0.4834 0.4609 0.4385 0.4165 0.3984 0.3633 0.3247 0.2866 0.2534 0.2202 0.1870 0.1670 0.1450 0.1201 0.0933 0.0601
0.5464 0.5317 0.5176 0.4980 0.4741 0.4497 0.4268 0.4082 0.3701 0.3325 0.2964 0.2632 0.2305 0.1968 0.1768 0.1553 0.1299 0.1035 0.0703
0.5625 0.5479 0.5322 0.5127 0.4873 0.4609 0.4375 0.4185 0.3765 0.3398 0.3066 0.2729 0.2402 0.2070 0.1870 0.1650 0.1401 0.1133 0.0801
0.5713 0.5552 0.5391 0.5176 0.4912 0.4639 0.4419 0.4194 0.3765 0.3398 0.3066 0.2729 0.2402 0.2070 0.1870 0.1675 0.1450 0.1182 0.0850
0.5801 0.5625 0.5449 0.5225 0.4951 0.4673 0.4458 0.4199 0.3765 0.3398 0.3066 0.2729 0.2402 0.2070 0.1870 0.1699 0.1499 0.1230 0.0898


Transient impact factor vs gain

1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.8501
1.7759
1.7017
1.6279
1.5430
1.4688
1.3877
1.2954
1.2021
1.1284
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361
1.0361

Hope this is more helpful than confusing.
Thanks. I'll be able to use some of that I bet. I'll try what I can of those and see what happens.
 

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Registered
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266 Posts
Mine does the exact same thing 12sws27, and its the fuel pump not the intake. I know this because I swapped the fuel pump while I still had the stock intake and FMU, and right after swapping to that 255 walbro pump it starting having the issue.
 

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Pill it till ya kill it
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459 Posts
Yep. Definitely the pump. Seen this happen alot.
 

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Registered
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230 Posts
I have a walbro 255 right now with the marine intake and 60's zero issues. Coldest start so far is 55 deg outside air with a cold engine and no hesitation. I have over 40 hours in tuning it though to have it running perfect with the forged motor. Where did you guy's get your walbro's? I have the one from highflow fuel pumps out of cali it's like a 100 dollar kit or so. Also running the marine FPR. The only thing I have different is the MSD boost a pump but I don't think that does much of anything with no pressure to it.
 

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Dig Or Die=I Die
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2,022 Posts
Discussion Starter · #11 · (Edited)
I got the high pressure lt1 255 kit. I used the same flex line like our stock pump has and I'm 99.99% it is on there good and clamped down tight.

I know a few guys have said "pump" but I'm having such a hard time accepting that. Sorry for being hard headed. I just really think it's in the tuning.

I'm thinking it either has something to do with Cranking fuel or Injector Controls.

I need an electric fuel pressure gauge. I wanna be able to log and see my fuel pressure at all time so bad. I hate that they're like $200....
 

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Sprayed 4.3
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585 Posts
I dont have any issues with mine.

I have them when its cold outside, but its a weak battery/alternator problem. I went through it last winter, neither ever gave out. Im afraid the weak one will show its face when it gets cold here pretty soon again.:(
 

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i need a paint job
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3,680 Posts
ive started my truck with the walbro and the stock intake in the teens before and i didnt have any problems. now with the marine intake its been in the 40's so far and it runs stupid rich still at idle, i still need to fix it, but it still will fire right up.
 

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I call her: NIGHTMARE
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2,124 Posts
impact factor? If thats what its called? The fuel is puddling on the intake wall instead of atomizing because of the cold weather. So you have to shoot more fuel.

Seems vaguely familiar in my head so i thought i would put it out there
 

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Dig Or Die=I Die
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2,022 Posts
Discussion Starter · #15 ·
There is a "Warm up" transient fuel section. I don't understand it so I have left it alone so far.

When I first started tuning the first time with the 24lb injectors I noticed the hard starts when the engine was cold after I messed with fuel to wall impact factor.

This time I noticed the hard starts before I touched the the impact factor gain. If my memory serves my right I don't think it did it when my VE tables were stock. I think it started as I tuned VE. I'll go right in a tune that has the stock VE and Maf tables and see what that does.

The hard starts are not because of cold weather. I mean when the engine is cold. So it'll do it at 80-90 degrees weather. It just only does it after the truck sitting and the engine is cooled off.

FWIW, I had the Walbro installed before the intake and never had the problem. Doesn't really mean anything though I guess. All I know is the fuel pressure is right and it never drops below 50. There is some bleed down. Might bleed down to 30 psi after an hour or so. I have some say that it shouldn't bleed down at all and some say a little bleed down is normal...

All I know for sure is that when my truck was all stock there was a little bleed down and my other truck has a little bleed down too. Never were then hard to start after sitting for a few hours. This is one of the reasons I think it has to be something that can be adjusted in the tune.

I think this one is going to take a little while to figure out.....

Right now I've been playing with Prime pulse mass and First Prime Pulse Mass under Fuel> General >cranking fuel. At first I thought the number should be higher. That seems to make it worse. So I think it's actually spraying to much fuel and since the engine is cold the fuel won't ignite right away.
 

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Registered
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266 Posts
Yeah definitely let us know if you figure anything out. It's an issue for my truck but at the moment I'm not so much worried about it as I am trying to keep my damn intake bonnet on the throttle body when it hits full boost. Yesterday I just went to MIR and right as a launched it off the line it popped off and the A/F ratio went to 10.0. Still ran a 14.2 even though I was super rich and leaking boost.
 

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Dig Or Die=I Die
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2,022 Posts
Discussion Starter · #17 · (Edited)
Yeah definitely let us know if you figure anything out. It's an issue for my truck but at the moment I'm not so much worried about it as I am trying to keep my damn intake bonnet on the throttle body when it hits full boost. Yesterday I just went to MIR and right as a launched it off the line it popped off and the A/F ratio went to 10.0. Still ran a 14.2 even though I was super rich and leaking boost.
Have you tried strapping it down with hose clamps? You take 2 worm gear hose clamps, cut the screw end off one, drill a hole in the ends of each clamp and bolt them down using the TB studs. Then use them to clamp your bonnet down.

 

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266 Posts
Don't think thats going to work. The throttle body bracket does not have a lip on it, and that is where its pulling up because the screws I drilled through the hose clamp, rubber piece, and bracket is rubbing the rubber piece and rips it apart.
http://img816.imageshack.us/img816/9168/enginecomplete.png
 

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Dig Or Die=I Die
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2,022 Posts
Discussion Starter · #19 ·

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S-series abuser
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694 Posts
With everything thats done to it, its hard to say. My bet is on the fuel pump though. Try cycling the key off on off on off on a few times without cranking the truck. Each time you cycle the key the pump should run for a few seconds. After you cycle it a few times see if it starts easier. You may have an issue with it not building pressure quick enough.

You could also make a little jumper with a fuse or circuit breaker to bypass the fuel pump relay essentially hard wiring the pump temporarily. Hard wiring the pump was mentioned earlier and this is the easiest/cleaniest way to do it.
 
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