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Discussion Starter · #1 ·
2001 S10 4.3. And before you ask, yes I've searched for a week. Too many answers with no solutions. This is a 4.3 that sat for a couple years. We got it running. It has a new fuel pump. Also swapped the ignition module and coil. Cleaned the MAF sensor. After about 10 miles of driving, the engine stalls out and starts to backfire if you push the throttle. If you turn off the ignition and restart, it runs fine for another 10 mi or so. A friend said that it could be the injection spider has gunk in it from sitting for 2 years. I prefer answers from people who've experienced this and fixed it. But any help is appreciated.
 

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Did you clean out the fuel tank? A list of everything you've done to it to get it running would help.
 

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I would put a fuel pressure tester on it and monitor it under driving conditions.
 

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A failing Crankshaft Position Sensor can act like that. They aren't too costly, but after installing one you must have a CASE relearn done with a high end bi-directional scanner. The PCM actually does the relearn, but only a 2 way scanner can tell it to do the relearn. I'd eliminate other possibilities first. Such as something blocking the exhaust or a failing Camshaft Position Sensor. Those do not need a relearn.
 

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Discussion Starter · #5 ·
Current list of things that have been changed.
The fuel pump has been changed the fuel filter as well. The tank was cleaned out. The crankshaft sensor has been replaced and the distributor. I've swapped out the ignition module with two used ones. It has a new coil.
 

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Discussion Starter · #6 ·
Update. It backfired and blew the plenum gasket out. One of the bolts was missing from the plenum. I think it was broke off. Today I'm attempting to replace the gaskets on the plenum and find out if the bolt broke in the hole.
 

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That certainly proves that you're getting fuel and spark. With a valve open.
Re check the wires on the cap. The passenger side are 2-4-6 front to back. Not true on the drivers side. It's 3-1-5
If that is correct, pull the cap and turn the engine by hand until the 2nd timing mark is at TDC. Your rotor should point at the 6 if your new distributor has the mark. or be 180 out. In which case turn the engine a full turn and it should be lined up. But now the question is, is it TDC on the compression stroke or exhaust? Since you're handy at taking things apart, pull the drivers side valve cover and watch the #1 intake valve as you rotate the engine. It should close just before you reach TDC for the timing to be correct. The #1 intake valve is the 2nd valve which is closer to the intake port. The 1st valve is #1 exhaust.
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The crankshaft sensor has been replaced and the distributor.:oops:
 

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Discussion Starter · #8 ·
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Well, the previous owner snapped off a plenum bolt and that's what caused the plenum gasket to blow out during a backfire. All plenum bolts were literally finger tight. I have one question for you S10 gurus. Under my plenum is the spider but it has no injectors and no wires. The parts truck I'm using for parts has the same plenum but has injectors and wires. I believe they're the same year. Not really understanding why mine has no injectors but still has a spider.
 

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View attachment 362126
View attachment 362125
Well, the previous owner snapped off a plenum bolt and that's what caused the plenum gasket to blow out during a backfire. All plenum bolts were literally finger tight. I have one question for you S10 gurus. Under my plenum is the spider but it has no injectors and no wires. The parts truck I'm using for parts has the same plenum but has injectors and wires. I believe they're the same year. Not really understanding why mine has no injectors but still has a spider.
Those bolts aren't very tight...at least they're not supposed to be. It shouldn't take much to get it out. A pic of both spiders you're working with would help to determine what years you're working with. If the are both '9+, it could be that one has had the spider upgrade...that would be a plus.
 

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Discussion Starter · #10 ·
I chose to put the parts plenum from the spare truck on my truck because they appeared to be the same. Got it running smoothly on Tuesday evening. Test drove it with no stalling. Took it to work with a round trip of about 30 miles and still no stalling. I guess a leaking plenum because of a broke off bolt can cause stalling. It used to take a couple tries with the key to get it to start before and now it immediately starts when you engage the starter whether the truck is cold or hot. I did learn a big lesson throughout all this. I barely moved the return fuel line and it shattered in my hand. I guess they get brittle with age.
 

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Discussion Starter · #11 ·
If most of you are still with me on this I got one more question. While I was fixing the plenum I changed out the blower motor and the resistor module. On my fan control I only have speed 3 and 4. Is it the dial switch or can it be something else?
 

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Discussion Starter · #12 ·
After a few days of running good it started stalling again. Some have claimed it's the IAC and some say a temp sensor. My last resort is double checking the fuel pump that the shop installed. Maybe it's defective or clogged.
 

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Discussion Starter · #13 ·
I like to follow up with my status for those with the same issues. Luckily I've got a parts truck and experimenting doesn't cost much. It was starting up perfectly and running really good but still stalling out after the engine got warmed up. My friend thought I may have water in my fuel so I started using heet. For the last few days it's been running perfect and not stalling. The only issue now is it started flooding it start up I believe. It was firing on first hit and now I have to hold the throttle to the floor to get it to run. Any ideas out there? A few posts on here claim it might be the pressure regulator under the plenum. What are your thoughts?
 

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Injector spider sounds like it's bad. They will leak around the fpr and flood the engine causing all sorts of craziness. When I say leak I mean fuel will POUR into the intake.
 

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Discussion Starter · #15 ·
Injector spider sounds like it's bad. They will leak around the fpr and flood the engine causing all sorts of craziness. When I say leak I mean fuel will POUR into the intake.
That brings up another dilemma. I put a gasket on the plenum a 2 weeks ago. This one's an oddity. It has the spider but does not have injectors. I've never seen anything like it in my life.
 

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That brings up another dilemma. I put a gasket on the plenum a 2 weeks ago. This one's an oddity. It has the spider but does not have injectors. I've never seen anything like it in my life.
If yours has the poppets, and it probably does unless it's been changed, the injectors are in the pod under the top of the manifold.
 

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Discussion Starter · #17 ·
If yours has the poppets, and it probably does unless it's been changed, the injectors are in the pod under the top of the manifold.
I can find the ones with the injectors new reasonably priced. I can't find the puppet style new so far. Should I get a new module and put my old puppets on it, or is that a bad idea? If my injector pod is leaking, what is the cause? Could it be the pressure regulator?
 

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What do you consider reasonable? Sometimes you have to pay to play. You can take the oem part number (12568332) and plug it into Amazon for a number of hits. I always preferred the usual name products...AC/Delco...Delphi...
 

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Discussion Starter · #19 ·
What do you consider reasonable? Sometimes you have to pay to play. You can take the oem part number (12568332) and plug it into Amazon for a number of hits. I always preferred the usual name products...AC/Delco...Delphi...
Sometimes aftermarket and refurbished items are good enough. The part number you gave me is for the injector type spider. I need the poppet style with built in injectors in the module.
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You don’t want the poppets. You’ll end up with the same clogged, poor running engine all over. The updated spider with the injectors at the manifold are plug and play.
 
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