ECM can change IAC as O2 sensor "reads" exhaust as too much or little air in that like messing w/ vacuum leaks until set 44/45 codes for big leaks or iffy injection.. So when you pull a plug wire, unplug injector etc during running IAC & RPM can change for same reason.
I'm waiting with bated breath, to hear what you find out.
BUT... I have a story.
I had a V6 car, 85 maybe 86 Very underpowered, bur still seemed to run *smooth* by my opinion. one of the fuel injector fuses was blown. 1,3,5, and 2,4,6 are on separate circuits.
It mystified me that I couldn't feel a misfire. The 2.8 is just so perfectly balanced.
This exact scenario ran our club "expert" around in circles for... too long a time.
Something that not everyone realizes... The EGR solenoid is powered by one of those fuses. If it shorts out, it can take out one bank of injectors.
Originally posted by jelly2m8: I think you and I could sit down and have a smooth glass of Whiskey
I'm a bottom shelf vodka kinda guy, but hey, if you're buying...
quote
Originally posted by Raydar: This exact scenario ran our club "expert" around in circles for... too long a time. Something that not everyone realizes... The EGR solenoid is powered by one of those fuses. If it shorts out, it can take out one bank of injectors.
So now. You jogged my brain. I think one bank has the plus one of the EGR circuit. and the other bank has the cold start injector.
I don't think that any of this helps Cliff, but I wanted to give info. Us old timers are not going to be around forever. I want to share what I can when I still have it in my head.
Originally posted by Raydar: the IAC will try to correct for it. Before killing cylinders, I would be inclined to unplug the IAC. Someone please correct me if I'm wrong.
It doesn't respond that fast. You will know when you unplug the dead cylinder, because nothing changes. You only have to unplug it for 2 or 3 seconds to notice a difference.
I have a friend down in indiana with an 87 GT. He hit a deer a few years ago and the car was out of commission for a long time. Last year i drove down to help him out with it. Lots of weird problems. One bank of injectors was not firing, the fuse was blown. We were dealing with some very strange problems regarding his MAP sensor. The ECU kept throwing a code for it, so i decided to take the MAP from my car and try it in his. Still throwing a code and wouldn't run, the harness was showing correct voltage and good ground from the MAP to the ECU connector, so i said screw it and threw my ECU into his car!(his is an auto, swapped PROM and the other chip) and it fired right up and ran beautiful.
Important bits are the injector bank not firing, but it was amazingly smooth still. Guess it gets a power stroke every 120° so its smooth still?
Then for spark testing. What I have always done is take my jumper cables and a spare spark plug, ground the plug by the threads to chassis/batt. Then pull a boot off from one cyl and plug it into my loose plug. Pull my fuel pump fuse and crank the motor. If the plug sparks, i move on.
Fun way is to pull the plug wire off at the distributor while the car is running, then trying to plug it back in while it shocks you the whole time. Only fought my way through 2 cylinders that way before my arm got sore from tensing up hehe
And that's how A_Lonely_Potato is turned into A_French_Fry.
Hahaha, good one. When I removed my distributor, I lost base timing, so to find it again, I had someone crank the Fiero without the fuel pump fuse, while using the light to time it before actually starting it. I ended up rotating the distributor by hand with ignition on, got a few good shocks from that, they weren't very bad, so I figured I needed a new ignition coil, and my car runs better now hahaha!
Automotive ignition systems don't carry anywhere near the continous current of ac systems. 480 Vac is no fun, 15kv can blow doors off a box. It's not the voltage, rather the current to be concerned with. The insulated spark plug wire is safe to touch while the circuit is complete, however once no path to ground it will find the best path, don't let that be you.
A_Lonely_Potato: Lots of weird problems. / so i said screw it and threw my ECU into his car!(his is an auto, swapped PROM and the other chip) and it fired right up and ran beautiful.
I had similar issues with weird problems on a 1992 Honda... So, I sent the computer to ECU Exchange for testing. They found that the computer had a bad power supply which created distortion on the reference and system voltages and the car rans beautiful after service.....
------------------ Original Owner of a Silver '88 GT Under 'Production Refurbishment' @ 136k Miles
Not to discredit anyone's suggestions, in regards to ecm. this company upfix.com fixed an abs module for me, so far so good. Don't know how they will do with ecms, 4 day to/from installed, and 5 months later still going.
