Engine One Side Hot, One Side Cold, Runs Like Crap
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
Sorry, that should have read, "have you" and not "how you" 
You need to pull all the injector connectors off, before you ohm test between connectors and D15 and D16. Running a wire from D15/16, to the engine bay, will make it easier.
I'm heading off to my 6:12 tee time, I'll check back in 5 hours.
You need to pull all the injector connectors off, before you ohm test between connectors and D15 and D16. Running a wire from D15/16, to the engine bay, will make it easier.
I'm heading off to my 6:12 tee time, I'll check back in 5 hours.
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From: Maple Grove Minnesota
Good luck with your round of golf Dan.
I put her up on jack stands to check the grounds at G104 and found two possibly three wires that have the casing burnt off? and very rusted.
Going to remove the nut and pull the harness up through the engine compartment and try to trace their origin to replace the wires. If unable to find their origin I’ll splice and solder new wires in as far back as I can get. I’ll post back results as soon as I get it done
I put her up on jack stands to check the grounds at G104 and found two possibly three wires that have the casing burnt off? and very rusted.
Going to remove the nut and pull the harness up through the engine compartment and try to trace their origin to replace the wires. If unable to find their origin I’ll splice and solder new wires in as far back as I can get. I’ll post back results as soon as I get it done
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From: Maple Grove Minnesota
Repaired two ground wires but could only replace about six inches of wire. Plugged the harnesses back into the ECM without all the blue wires, hooked up the battery turned the key and it runs the same as before, didn’t change a thing. 
I’m not finding a harness connection in the engine compartment for either bank of injectors. It looks like the injector wires go directly into the firewall?
I’m not finding a harness connection in the engine compartment for either bank of injectors. It looks like the injector wires go directly into the firewall?
Team Owner
Joined: Jan 2003
Posts: 20,324
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From: Summerland B.C. Canada
As for repairing the grounds, that was not going to change the "cold one side" problem, that was to clean up the PO's mess and not supply grounds to things that should get ground from the ECM.
I think your problem is the connection between ECM and one bank of injectors.
According to my FSM schematics, D15 and D16 are common inside the ECM.
If you find continuity between the 2 ends of harness on both banks, wiggle the harness while testing, to see if there is an intermittent open. If there was to be one, I would think it would be between the splice to 4 wires and the ECM. The splice is likely at the start of rectangular loom.
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From: Maple Grove Minnesota
Just went out and checked each injector connectors. Ran a wire from D15 the driver’s bank and the needle on the ohm meter went to 0 on each connector. Did the same for D16 to the passenger side and got the same results. Wiggling the wires had no effect on the readings.
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From: Maple Grove Minnesota
Forgot to mention I checked to see if one side was still cold when I started the car yesterday and both sides seemed to be equally warm.
After thinking about how it was running it seemed to be more fuel related sucking a lot of air when I put the gas to it. (It was also very hard to start). I just put my pressure tester on it and have 0 pressure and can not here the pump come on when I turn the key. I also turned it over and watched the gage and still no pressure. Also when I last scanned it came up with a lean condition. I guess it's time for a new fuel pump?
After thinking about how it was running it seemed to be more fuel related sucking a lot of air when I put the gas to it. (It was also very hard to start). I just put my pressure tester on it and have 0 pressure and can not here the pump come on when I turn the key. I also turned it over and watched the gage and still no pressure. Also when I last scanned it came up with a lean condition. I guess it's time for a new fuel pump?
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Thread Starter
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From: Maple Grove Minnesota
I forgot the ECM wasn’t hooked up so the pump is working but when I turn the key on the pump comes on and jumps to about 48lbs and within 30 seconds it drops to 15lbs what causes that? I replaced the regulator a couple months ago.
Instructor
Joined: Aug 2009
Posts: 146
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From: Broadway Virginia
Just guessing: One or more leaky injectors, leaky FPR (fuel press reg.), and then there is some sort of a potential issue with a pressure compensator or something like that on the output side of the fuel pump which I have read sometimes leaks down pressure.
In my vehicle's case it was leaky injectors causing a prolonged hot crank.
One thing is for sure, it should not leak down that far that fast. Not sure whether it would cause just one bank of injectors to not work properly. Seems it would affect all of them.
In my vehicle's case it was leaky injectors causing a prolonged hot crank.
One thing is for sure, it should not leak down that far that fast. Not sure whether it would cause just one bank of injectors to not work properly. Seems it would affect all of them.
Last edited by walter schweigert; Jun 20, 2010 at 10:54 AM.
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
So it's not cold on one side, that's good news, too bad it wasn't checked before ohming the injector harness.
Follow the steps in this link, to isolate where the pressure loss is. Mine was the pulsator, above fuel pump.
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
Follow the steps in this link, to isolate where the pressure loss is. Mine was the pulsator, above fuel pump.
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
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From: Maple Grove Minnesota
Thanks Agent 86, I thought the test pinching off the inlet and return lines would be easy to do but Nooooooo you can’t get at the flexible hoses to pinch them off without draining the coolant and removing the lower radiator hose. Oh well! Have to do what you have to do just not for a few more days.
Burning Brakes
Joined: Oct 2009
Posts: 773
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From: Minneapolis MN
Hey keith.Been very busy lately but sounds to me like your computer is bad & may have been damaged from the PO wiring patches.You checked the harness from the injectors to the computer from what it sounds like.Did you switch all 4 injectors over to the other side.I was taught that one bad injector on one side can cause all the injectors on that side to not work(old GM saying).Make sure no matter what if it is the computer you get that wiring fixed properly so you don't possibly short out or ruin the next computer.It sure helps when people have that FSM to go by.Good job Agent 86
Team Owner
Joined: Jan 2003
Posts: 20,324
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From: Summerland B.C. Canada
Thanks Agent 86, I thought the test pinching off the inlet and return lines would be easy to do but Nooooooo you can’t get at the flexible hoses to pinch them off without draining the coolant and removing the lower radiator hose. Oh well! Have to do what you have to do just not for a few more days.
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From: Maple Grove Minnesota
It lost fuel pressure when pinching off both the supply and return lines (individually) at the tank so the FSM says it’s a leaking injector. The po said he replaced them and I found a UPS box containing some injector boxes with the name Bostech which are remanufactured so it doesn’t surprise me if one or more is leaking.
What size and brand should I get for a presumably (I have no history on this car) stock engine?
What size and brand should I get for a presumably (I have no history on this car) stock engine?
Instructor
Joined: Aug 2009
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From: Broadway Virginia
That would be a question for Jon at www.fuelinjectorconnection.com.
There are original replacements, which is what I installed on mine, and then there are the Bosch III design, which may appear cosmetically different from the originals but have gotten rave reviews.
There are original replacements, which is what I installed on mine, and then there are the Bosch III design, which may appear cosmetically different from the originals but have gotten rave reviews.
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From: Maple Grove Minnesota
Went looking for a wet plug this morning but didn’t find any. I energized the fuel pump a dozen times and pulled all four driver’s side plugs and did the same for the passenger side but no wet plugs.
Wondering now if I was able to pinch off the feed and return hoses good enough and the drop in pressure is still pump/sending unit related?
I also pulled the vacuum line of the FPR and there was no fuel in it and being new it should be fine.
Wondering now if I was able to pinch off the feed and return hoses good enough and the drop in pressure is still pump/sending unit related?
I also pulled the vacuum line of the FPR and there was no fuel in it and being new it should be fine.
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From: Maple Grove Minnesota
I picked up a Noid set and all eight injectors are getting a signal so it’s not running on four cylinders. Must be a fuel issue this time? thus the drop in pressure. As I mentioned I didn't find any wet plugs.
Is there any tests to check the fuel pump or should I just purchase a new sending unit and pump?
Is there any tests to check the fuel pump or should I just purchase a new sending unit and pump?