Car broke down other day. I'm getting spark from my wires, fuel pressure is good, I replaced MAP sensor. Had a code 34 and a 48, but this came up after I had plugged the battery back in. Checked voltage coming from wire harnesses. MAF code comes up but the car would still run decent even if it was broken right? I do have an exhaust leak at DS exhaust manifold(this considered a vacuum leak)?

I'm running out of ideas here. Just replaced the PCM like 5 days ago too and everything ran fine after that. THe car broke down on me, sputtered and came to a stop with backfires after only going 15mph and 2.5k rpm. THe car will barely start now but and not idle AT ALL, it just jumps around at 100-800 rpms and is vbery very rough. PLease help!!!

 

An exhaust leak won't cause it to not start. Have you tried disconnecting the MAF and trying to start it?

How are you testing for spark? You need to use a spark tester (available at any auto parts store) and make sure it'll jump about 3/4"...a weak spark will look visibly ok to most people, but won't work for crap on these cars. Have you pulled the coil wire and inspected it for white corrosion? That's also common on these cars...good luck.

Also, if all worked well after the PCM change, double check all the connectors/harnesses/grounds.

 

Since it is OBD-I the car will not run right or at all without the MAF in proper working order.

 

The car will run fine with the MAF disconnected...it reverts to speed-density mode.

 

OKay, I did check the oil and it smells a lot like gasoline. Oh sh*t? I checked to see that the knock module on my PCM was still in place. Plugged PCM back in, unplugged MAF sensor and tried starting the car again. Same thing, this time it wouldn't start at all.

When I checked for spark last night I used a spark tester on 2 front wire and with about 1/2 inch gap and watched it spark 5-6 times before calling it good.
I assumed that it couldn't be the opti spark or ignition module since I was seeing spark at the spark plug wires themselves...

When the car broke down I did not see any smoke at all. When my car was still running it would never smoke. When I had it idling barely about 2 hours ago, there was no smoke. I really hope this gasoline smell in my oil is from turning the car over off and on since last night, is that possibble lol. Thanks for the great advice so far.

 

Pretty sure thats OBD-II, I have a 97 converted to OBD-I, if my MAF isnt plugged in the car isnt running.

 

If your oil smells like gas take out one or more of your spark plugs. If the tips are wet then they are fouled and that will cause a no start.

 

Did you have the computer programmed recently? What work has been/was done to the car? Does it idle if you hold the throttle open a bit?

As for the MAF bit, I'll double check tonight, but I'm fairly certain my 95 will start with the MAF disconnected. We used to work on a buddies 96 (has since been converted to OBD-I though) on occassion, and I could be getting the two confused.

If you have access to another MAF, definitely give that a shot.

 

I did not have the PCM reprogrammed. I ruined my original/old one and had a core-exchange done with Auto Zone. They took all my vehicle info including my Vin#, sent me the new one, I installed it and everything ran fine for 3ish days and then I broke down on the Interstate. Had the car towed back and here I am.

When I do manage to get the car started the throttle response is nothing. If I give it a little throttle while it's jumping around missing from 100-900 rpm it will do nothing.

I have been repeatedly testing this and that and in the process have been trying to start the car off and on as well. Could it just be extremely flooded from all the gas it's been getting and has not been burning it off? Is this why there is fuel in my oil? Is fuel in my oil a serious problem?

I will pull a plug off and look at the tip of it. I'm guessing it's gonna be pretty wet as I've been started the car over and over since last night. But ya it will start for a little while but it definately seems like only 1-2 cylinders are firing and that's it. Hmmm.. Lemme go pull a plug!

 

If they are wet then you have to remove all of them and clean them or replace em. The car won't stay running because it won't burn the fuel on the plugs. How did it act when the car broke down?

 

The plugs are indeed pretty wet, black tipped and old looking, they say AC on them. I'm going to try to find some NGK TR-55's and Wires tonight but am pretty sure that alone isn't going to solve my problem but the car needs it. Maybe need a new ignition module as well, the power from the ignition harness is at 11.5ish volts but I can't seem to get an ohm-resistance reading like my Haynes manual states.

The way my car acted when I broke down: I was cruising down the Interstate nice and easy about 10 miles, went to turn around on an over pass and go home, when I pulled onto the ramp doing about 15mph and 2.5k rpm due to some bumps and a cattle guard in the road the car just died.

I believe I was about to give the car some throttle and it made a couple of popping sounds, backfired was missing like crazy, the idle went all eratic on me around 100-900rpm and it just died right there on the ramp. I pulled the car off and managed to back up about 70 feet onto a pullout to get it towed away, while it was in reverse it barely went through all the misfires/idle trouble. I didn't notice any smoke at all, it's never smoked since I've owned it and the oil pressure is all good, just smells alot like gasoline now! (Is this really bad to have fuel all in my oil?), I know chainsaws run w/oil in fuel lol. But yes that is how it happened and behaved when it stopped running ok...\

Thanks for great feedback so far, I feel like I'm getting somewhere slowly but surely, a mechanic is a last resort for me right now!

 

Once you change the plugs see how it runs. You may have a wiring problem or the opti took a dump.

 

FYI - I just tried my 95 (OBD-I) with the MAF disconnected and it starts fine...the fans come on along with the SES light, but it idles perfectly.

 

Just a thought... its running fine, it backfires, and you have a code (34) for the MAP sensor (MAP low, vacuum high) and your MAF seems to die. You replace the MAP sensor.

Is it possible you had an intake manifold backfire that was powerful enough to damage both the MAP sensor and the MAF sensor? If so, is it possible it blew the intake elbow off, or some of the vacuum lines to the intake manifold?

 

I've double checked just about all I can from the top of the motor while trying to get it going again. All the vaccum lines were still held in place (just replaced those). Ya I replaced the MAP sensor and tried to run the car with MAF not plugged in and with it plugged in, still the same symptoms.

Before I even checked for the code my dumbass had the battery disconected and was pulling things apart all frantic like. If the PCM did have any codes stored from when the time it happened wouldn't it be erased? Then when I did hook up datamaster it gives me the 34 and 48 is all when trying to run the vehicle.

I got a new AC Delco optispark on the way from samtaylor.com and ngk plugs, taylor 8mm wires and a new ignition coil. I hope this will correct the problem but am only making a logical guess at it with feedback from others.

ALSO: I believe there is good reason for it to be my opti too. When the car was warming up the same day it sounded like the pulleys were squeking real bad. I took a can of WD40 and went to town on them and think I drenched the opti spark in the process. I took it to a car wash after that to rinse the outside of my car off and then took it down I40 windy as hell. Seems like it adds up into a pretty good guess of what it might be.,,,

Thanks again