I'm starting to hate obd1
#1
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Car: 1988 IROC-Z Camaro, 1981 Trans Am
Engine: 350 TPI, 301 N/A
Transmission: 700r4, 350thm
I'm starting to hate obd1
I have been having trouble with my car lately. It's a 350 tpi. It started about a month ago, it ran perfectly fine until a friend asked to go for a ride along. I took him and drove it a bit hard, but nothing over the top. I shut it off and an hr later tried to start it to no avail. Frustrated and needing to be somewhere i left and I let it sit abt 4 or 5 hrs, came home and it started right up with no problem. A few days go by and it's running fine until I start it one.time. Check engine light, running bad. I ran the codes, and it's the same that have always given me trouble; 32 and 41. I started trying to diagnose it by checking and unplugging sensors to see if there would be any difference and some sensors made it run worse, done affected nothing, but when I unplugged the maf it ran better-smoother idle, more crisp throttle response, no stumble. I swapped a good maf from a friends car onto it and it ran fine with no codes, I started it several times to be sure. I bought a remaned maf and put it on, the next day the codes came back.
It runs 3 different ways I've noticed: fine (no check engine light but rare to happen) poor (feels like a 305 almost, feels like it's pulling timing out or running real rich) or really bad which it stumbles alot, has no power to speak of and feels like a v6.
I have checked all the following and they are good: all injectors ohmed well, took apart distributor and tested icm and coil, cap and rotor looked good, checked tps and it was good, checked it and it was not sporadic when slowly increasing throttle. Sprayed seafoam down the hole for IAC and let it sit overnight to clean it some. Fuel pump is2 years old and fuel pressure is good. unplugged knock sensor and it didn't affect anything (from what I recall). I unplugged the cts and it ran horrible. Checked all ground, all are fine.
What also makes it weird is 1 in every 15-20 starts it'll run fine, just like before all this started. I'm not positive on this, but it seems to help if the car has ran and warmed some, sis for 10 min or so.
Really at a loss here guys, all help appreciated! Thanks in advance!
It runs 3 different ways I've noticed: fine (no check engine light but rare to happen) poor (feels like a 305 almost, feels like it's pulling timing out or running real rich) or really bad which it stumbles alot, has no power to speak of and feels like a v6.
I have checked all the following and they are good: all injectors ohmed well, took apart distributor and tested icm and coil, cap and rotor looked good, checked tps and it was good, checked it and it was not sporadic when slowly increasing throttle. Sprayed seafoam down the hole for IAC and let it sit overnight to clean it some. Fuel pump is2 years old and fuel pressure is good. unplugged knock sensor and it didn't affect anything (from what I recall). I unplugged the cts and it ran horrible. Checked all ground, all are fine.
What also makes it weird is 1 in every 15-20 starts it'll run fine, just like before all this started. I'm not positive on this, but it seems to help if the car has ran and warmed some, sis for 10 min or so.
Really at a loss here guys, all help appreciated! Thanks in advance!
Last edited by Black88Z; 07-22-2014 at 01:16 PM.
#2
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Re: I'm starting to hate obd1
I think the OBD1 is working fine, it may be the 26 year old wire or parts in the car. I had a 86 Monte that would spark, but it wasn't a hot enough spark. Turned out to be a bad pick up coil in the dist. Just a thought. There is nothing more frustrating than a intermittent problem like that.
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Car: 1988 IROC-Z Camaro, 1981 Trans Am
Engine: 350 TPI, 301 N/A
Transmission: 700r4, 350thm
Re: I'm starting to hate obd1
haha what I meant is obd2 makes diagnostics alot easier. But I forgot to mention that, I ohmed out the pick up coil and it tested good. I had the icm tested probably 5 or 6 times to be positive it was not that being flaky lol.
Anything else you can think of? I'm really stuck with this one
Anything else you can think of? I'm really stuck with this one
#4
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Re: I'm starting to hate obd1
I would start with the basics, and check all vacuum lines for cracks and all ground connections even back to the ecm. The ecm's are pretty reliable themselves, but the wire connections and grounds can cause a lot of problems. Here is the ecm pin out. http://austinthirdgen.org/mkportal/m...ine_wiring.gif Here is the whole wiring diagram. http://www.austinthirdgen.org/index.php?pid=19
Last edited by red rock; 07-22-2014 at 08:34 PM.
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Car: 1988 IROC-Z Camaro, 1981 Trans Am
Engine: 350 TPI, 301 N/A
Transmission: 700r4, 350thm
Re: I'm starting to hate obd1
It's been a while, but I actually did go back and check every pin on the ecm. Everything was ok, but that was a while ago.
Do you think that the remand maf is really the problem? It seems odd, but I guess entirely possible.. I can ask to try my friends maf one more time, but I'm tempted to go ask to swap mafs at the parts store.
Other than the maf, this doesn't scream anything usual does it? I never seem to get the "common problems I always get the odd ball stuff lol. If the maf isn't the problem I'm still not sure where to go with it.
Do you think that the remand maf is really the problem? It seems odd, but I guess entirely possible.. I can ask to try my friends maf one more time, but I'm tempted to go ask to swap mafs at the parts store.
Other than the maf, this doesn't scream anything usual does it? I never seem to get the "common problems I always get the odd ball stuff lol. If the maf isn't the problem I'm still not sure where to go with it.
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#8
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Re: I'm starting to hate obd1
It's been a while, but I actually did go back and check every pin on the ecm. Everything was ok, but that was a while ago.
Do you think that the remand maf is really the problem? It seems odd, but I guess entirely possible.. I can ask to try my friends maf one more time, but I'm tempted to go ask to swap mafs at the parts store.
Other than the maf, this doesn't scream anything usual does it? I never seem to get the "common problems I always get the odd ball stuff lol. If the maf isn't the problem I'm still not sure where to go with it.
Do you think that the remand maf is really the problem? It seems odd, but I guess entirely possible.. I can ask to try my friends maf one more time, but I'm tempted to go ask to swap mafs at the parts store.
Other than the maf, this doesn't scream anything usual does it? I never seem to get the "common problems I always get the odd ball stuff lol. If the maf isn't the problem I'm still not sure where to go with it.
#9
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Car: 1988 Camaro
Engine: 377
Transmission: TH350; Circle D 4200 converter
Axle/Gears: Ford 9"
Re: I'm starting to hate obd1
Most of the remanufactured parts (particularly wired components or ignition related) from general parts stores aren't good. I agree with this completely.
#10
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Car: 2000 Trans am vert 87 GTA
Engine: 5.7/5.0
Transmission: T56/700R4
Re: I'm starting to hate obd1
had the same problem with a remanufactured compressor from advance auto. installed it and set it up perfectly just for it to blow up on me after 1 day..... returned it bought a brand new one and it has been cooling for over a year with no issues.
#11
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Car: 86 IROC
Engine: 5.0 TPI
Transmission: 700-R-4
Axle/Gears: 2.73 open
Re: I'm starting to hate obd1
It's been a while, but I actually did go back and check every pin on the ecm. Everything was ok, but that was a while ago.
Do you think that the remand maf is really the problem? It seems odd, but I guess entirely possible.. I can ask to try my friends maf one more time, but I'm tempted to go ask to swap mafs at the parts store.
Other than the maf, this doesn't scream anything usual does it? I never seem to get the "common problems I always get the odd ball stuff lol. If the maf isn't the problem I'm still not sure where to go with it.
Do you think that the remand maf is really the problem? It seems odd, but I guess entirely possible.. I can ask to try my friends maf one more time, but I'm tempted to go ask to swap mafs at the parts store.
Other than the maf, this doesn't scream anything usual does it? I never seem to get the "common problems I always get the odd ball stuff lol. If the maf isn't the problem I'm still not sure where to go with it.
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