I am working on a car for a friend its an 87 Iroc 350 tpi auto. it has 98k miles on it.

First off it runs like crap, you push the peddle it stumbles and backfires through the intake, then gets up and goes. it doesnt smell too rich and there is no smoke. The fan runs constinuosly even with no key in the igntion.

I have ohmed all the injectors they were all 16.2 ohms so they are all good.
I pulled the plugs and two were finger tight, put in new delco plugs gapped to .035. they needed to be changed,kind of rust looking deposits on the loose ones, the rest were perfect tan. Still runs the same after this.

I pulled codes 14 high coolant temp, 22 low tps volt, 33 high maf volt, 36 miss at distributor or maf burn off, 44 o2 sensor lean

I think the maf and tps came when I tried unplugging them to see if it would change anything. other than that either the coolant temp sensor is bad or the o2 is bad or distributor cap or rotor needs to be changed. maybe the fuel pump is not putting enough psi out but i figured it that was it, it would run worse at higher rpm. I am going to check fuel pressure when i get home.

I ordered some new plug wires too, but i dont think it will do anything.
Also the tach doesnt work does anyone know what to check?

Let me know if I have missed anything.

 

Keep in mind that an injector can ohm out fine and still be bad. What's the vacuum at idle? I usually disconnect the O2 sensor to keep it in open loop mode while troubleshooting. Get it running good that way first, then troubleshoot any closed loop problems.

 

I second the above (about troubleshooting in closed loop). Get ahold of a Helms shop manual (not Chiltons) and follow the diagnosis charts for those codes. Or find someone with a scanner who'll upload it for you (sorry, no scanner!)

 

I have a mastach cable I need to download the software for it again and wait for my damn laptop battery to show up.
Thanks for the responses, i'll try to unplug the o2 and see whats up.

 

does anyone know why the fan runs even with no key in it? Or why the tach doesnt work?

 

I would guess the fan relay is stuck (up my the brake booster, I think it's the left one, but I'm not sure).

 

the coolant temp sensor can do all that.. cuz if its sayin the car is overheating it will retard the timing.. so that could b the problem the fan relay could b stuck but the coolant temp sensor also puts the fan on certain cars.. im not sure bout this 1 thou but those r some possibilites

 

well I had the car scanned most everything looked ok. but now the check engine light is on continously wereas before it was just on for a sec at a time..

I tested the fuel pressure. 20psi! it most likely is a bad pump. I noticed when I filled it up with gas it ran alot better than when it was near empty.

I tried swapping relays it didnt do anything the fan still runs constant. I unplug it when i park the car.

Where is the coolant temp sensor located? I bought a new one already just have to put it in.

 

on identifix there are a lot of confirmed fixes with similar symptoms that had a confirmed fix of the distributor