bufmatmuslepants

iTrader: (3)

I'd plug the air ports with a cummins diesel oil drain plug from autozone, google it and you'll find the right year plug to ask for, I think it's a 24 valve drain plug. That'll get rid of that exhaust leak which could be having an effect.

hrcslam

Alright, I did more troubleshooting. I tested the TPS and found it to be good. IAC is working too. I pulled the opti to find nothing wrong with it. So I pulled the engine coolant temp sensor and ohm'd it out. I found it reading 1.4K ohms at 80°f ambient, that's quite a bit low. So I got a new one and ohm'd that one out the same 1.4KJ Ohms at 80°f ambient. So, I took the one out of my Camaro and that ohmed at 3.4K Ohms at 80°f ambient. So I threw the one from my Camaro in and she started right up and ran great.

Then I took it for a test drive. Instant bogging and the symptoms returned, again. Argh! Code 15 popped up, Coolant Sensor Low Temp. So, I shot the sensor again and found it reading about 260ish Ohms, so ~200°f coolant temps. I shot the wires from the sensor to ground the the PCM respectively. I found the yellow wire had an intermittent positive connection at the sensor plug. I replaced the plug and decided to swap out my sensor (to put back in the Camaro) and install the new one and ohm'd it out to 260ish ohms. So about the same. I cleared the codes and ran it again. The codes didn't come back and she started right up and idles fantastic now. But, she still bogs down hard with throttle input, and fluctuation the throttle up and down will get the RPM up to about 3500 before it's gassed out.

I really don't have the funds to buy another 12 Pin OBD1 cable. Does anyone know how to use my 16 pin OBD1 cable on the 12 Pin set up? Jumper wires? I really need to get the data logger on it. I'm leaning to O2 sensors now. But, I hate shot gunning parts.

Anyone else experience something similar? Maybe I'm over looking something?

Thanks in advance!

Ray

hrcslam

I tried to remove the Air port, no bueno. It is out of round and stripped in! Replacing the manifolds would actually be better. I may talk to my buddy (the guy that owns the Vette) and see if he wants to buy some headers instead. If I can get my 16 pin cable to communicate with the 12 pin ALDL port, then I should be able to emulate the ECM and write a tune for him. He's already got a PCM4Less chip in it (to delete the VATS), I gotta find out if that chip is re-writable or not.

That's something I never really looked into; chip burning. I have no idea what chips to use, or what burner to use, or what program to use to write it all. I'll start a new thread on that cause my brother has a 1995 TBI Silverado we'd like to do the Vortec Head swap on and I'll need to tune it for that too.

lt1-xjs

It's easy to misalign the prongs on the pcmforless adaptor. Make sure they are all inserted. You might also remove the adaptor and try just the chip.

bufmatmuslepants

iTrader: (3)

A TBI motor isn't worth a head swap unless you fix the choke point of the TBI which is like a 2 barrel carb, its tiny. Those TBI motors only run to 4000rpm stock, they just can't get enough air last the TBI to run higher, and the 2 bolt mains will handle more but not a lot more. That rotating assembly is heavy and big, with big rings. I love the TBI motor for what it is, a low end torque monster, but if I wanted performance I'd do an LT swap.

LT1

iTrader: (1)

I know this might be unrelated, but while watching the first video noticed number 6 spark plug arcing to the exhaust shield. Just thought that might cause a issue.

Nostang

iTrader: (4)

Did you try ohming the IAT sensor? It can have a very similar effect as a faulty coolant temp sensor. Also, when you checked the fuel pressure, did you check it while under load? Are you able to borrow a scanner from autozone or similar to see the 02 readings and actual pcm sensor readings?

Also, that video sounds like the car is getting air and spark but no fuel. If it were a faulty injector it would still rev but would be rough. Sounds like it is choking out and starved of fuel. Sometimes the line can partially blow off in the tank and still provide pressure at idle but not under any load.

The rattling sounds like a burned out cat and the ball is rolling around in the exhaust. I had that happen on my car back in 96 with 10k on it while driving on the highway after some nitrous pulls. If the cats are clogged, you would most likely feel air coming between the head and exhaust manifold while reving up that high. It could be a clogged cat as the symptoms are similar to fuel starving.

hrcslam

Well, it's been a while. But, I thought I'd update on this.

Turns out is was plugged fuel injectors and the new MSD Optispark was bad. MSD rebuilt the Opti and the injectors were cleaned. Runs like a champ and has been for the last year or so.

SS RRR

iTrader: (2)

Where TF have you been?

hrcslam

Busy. LOL. Spent the last year or so getting out of aviation my mobile auto repair business off the ground. I'll be updating my build thread in a couple months hopefully.