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Discussion Starter · #1 ·
In 2002, my Son called me and ask me to be on the 'look-out' for an S-10. He had a 1985 S-10. The body and running gear was in bad shape. The 2.5 E code 4 cyl with 178,000 miles was infact still running. I found a 1989 S-10, 'no engine-good title'. . . priced right. The '85 engine was installed, with the model 300 TBI. The wire loom went through some snip / modification for the injector connection and some changes inside the cab instrument panel. {just below the ECM under the dash} The truck ran great for a few years until the # 3 piston cracked and turned the block into salvage weight. It sat in his drive way for two years, he purchased a new pickup and offered me the S-10. Now thats the name of that tune.
The S-10 was parked on my open air base rock car port in 2005. The blown engine had been removed and was in the bed. The first thing I did was put 5 gals fuel in the tank with some 'sta-bil'. Went on the search and found an E code 4 cyl. {1986} real cheap... my machinist called and told me I had lucked out. The block and head was in great shape. It would take a rebuild. I give him the O K to bore it 30 over, turn the crank, rebuild the head, new roller lifters / push rods...re-cond rods /camshaft. I had made that simular request to a machinist in 1959 to bring a '48 Merc V-8 flat head back to life. I wanted a 'new power plant' for the restored 1937 Ford Coupe. The S-10 will receive the same, a new engine. This is one of two post I will make on the problem/s that has come up on the S-10. I did return for some old iron memories of the '37 Coupe. Will share when I find uot the procedure.
 

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Discussion Starter · #2 ·
had a message for sending, but lost my connection. After 4 years, the new engine 2.5 E code 4 cyl was installed. Many fuel and electronic problems popped up. Got the engine running after replacing the fuel pump and the 10 amp fuse to the ECM. it started and ran with a fast and rough idle. After a few minutes, it was running good. { all sensors / injector / were old parts} For two weeks, the truck ran great. It lost power and would not idle. Big time flooding. Plugs fouled. Replaced TPS, idle control, fuel regulator. Continues to run poorly and fouls plugs quickly. Many changes have been made to the '89 S-10 systems. It has a new '86 power plant with '85 TBI model 300 injection. Have many more parts that can be replaced, ??? injector, TPS,coil, distributor, and the mystery ECM under the dash. The truck has gone through some tampering with. But it did in fact run well for two weeks for me. I need some info on just what the problem area and suspect part is. Have no problem with the purchase of needed parts, but replacing part after part is not an option to fix or resolve my problem. The truck did run well with just the replacement of the fuel pump and the 10 amp fuse. One or even more of the ???'s I listed is the main suspect. I will use today and tomorrow to restore some of the energy I have spent on the project and check the S-10 forum for any helpful post/reply. Will study more from the Chilton & Haynes manuals on both ignition and fuel systems. That's the name of that tune.
 

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Discussion Starter · #3 ·
The throttle pos sensor was not replaced, it was the MAP sensor I replaced. I have got rid of my '87 Firebird, '84 Dodge charger, '63 Scout, even my favorite '78 Delta 88 Olds. The S-10 is my only ride that remains. Have had no mobility for over two weeks. I will continue to have a good mood for this problem to be resolved.
 

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Check the CTS Sensor...
 

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Discussion Starter · #5 ·
Check the CTS Sensor...
Went out this morning early to bond with and verify my interest in resolving this problem. Fact continues to remain . . . The S-10 is a model 1989. The new rebuilt engine is out of a 1986 S-10 E code. The TBI/ intake / supplies fuel via model 300 injection system. Wiring at the injector was spliced with the model 300 connector. The CTS in the wire loom was also cut and spliced on the '86 sending unit. I will trace that out. I looked at the ECM under the dash and many wires to the instrument have been cut and spliced. The ECM has a small 'piggy-back' attatched, approx 3 x 3 x 1/2 with a few wires. I did compare it to an '88 ECM / 2.5 in my spare parts box. It has a 24 & 32 pin connection. It is obvious that lots of modifications have been made to the wire loom. However, after a period of four years, the engine fired right up and I letit idle for over 2 hours while I did my Checks. It never did overheat, but it was running rich. It ran great for two weeks. Started right up and had good power. The distributor and coil are suspect. The distributor is a REMANF part, the external coil is off of a '85 model. My cost guess for these two parts will be approx $170. The CTS I removed from an '85 & '86 block, one of them has been installed. The other in my spare parts box. I will find out more detail on the ECM that is in the truck. Thanks for the heads up on the CTS. I will try the spare CTS this morning. Get my Son-in law to taxi me to Auto Zone and check on the cost of the dist / coil / new CTS.
 

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Test the CTS with an ohmmeter, compare the resistance to the chart in my signature.

The small piggyback board is probably from a later model duke setup and is the DRAC module (for the digital speedo- no cable on that model).

Running rich could have to do with the CTS reading too cold, the O2 sensor reading too much O2, an exhaust leak (usually the crappy welds on the exhaust manifold, but you never know...), a leaky fuel injector, etc......
 

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Discussion Starter · #7 ·
Test the CTS with an ohmmeter, compare the resistance to the chart in my signature.

The purchase of the distributor and new ignition coil was yet two more guess replacements. When I got squat results after replacing these two parts, That thought of something I had done or not done may have been the cause. I picked up tools Monday and started the truck to move it up on the grade base rock so if it did come that rain, a slight raise in the front would run out of the bed. I had put a few these under the tool box. The engine fired up, but I heard this noise I had heard before but could not I D. The engine stopped and it locked up. I went into the house and I was not the happy camper. Did not get any rest Monday night, I got up at 3: 30 and went through this head of mine on what it could be. The rain had stopped and I set up a drop light. Had me a cup of coffee, good daylight, I was under the hood and started to remove the spark plugs. The #1 and #2 cylinders were O K, the # 3 cylinder spark plug was coning out hard. When I removed the plug, it was smashed. Looked into the plug hole and found the problem from the 'get-go'. I could see a piece of metal in the cylinder. My small magnet would latch on to it, but it was bigger that the spark plug hole. Took the valve cover off and found the valve spring broke in four pieces. Found the two keepers and all other parts. None of these parts could get in the cylinder from under the cover. The rocker arm was off , pushrod was bent. One ear of the pushrod guide was bent.The piece in the #3 cylinder is no doubt the head of the intake valve. When the problem first happened, that small piece of spark plug porcelain did not let the intake valve close all the way. It don't take much for the piston to hit . It was bent right at first. That noise I heard was the valve being removed from its stem. I got into the engine compartment and checked it out. It is loose inside the cylinder. I will take a much needed nap today and start fresh in the morning. The cylinder head must come off. Lots of other parts will also need removing. I will keep any bad thoughts of the piston damage on the back burner. If all works out, I will have the head at the machine shop and the bad valve / parts replaced. Should have better results . There is no sign of the piece of spark plug porcelain in the cylinder. Yeah, I made a big faux pas driving the truck six miles to the house. It was running bad, but it got me home. I did infact check the # 1 cylinder, should have went right down the line on all cylinders. Would have found the bent valve with my pressure test. I think I am on the path and have 'Named the Tune'. Will replace the CTS. The blade connection turns in the brass body.
 
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