More issues. Need some help.

[cornfish]

Hey Guys,

My '98 GTS now won't start, so I need help pretty bad. Let me try to explain the issues I am having right now.

- Was getting an Idle hang when the car was hot so I replaced my 02 sensors and got sensor extenders because of the aftermarket headers
-- Did not fix the idle hang at all
- Car was running hotter than normal (not overheating) so I pressurized the system and tried to get the air out
-- Some air came out but didn't fix this at all
- AC was not working so I took it to the shop to get it looked at
-- AC now works great
- Drove the car on a 3 hour trip and the car seemed to be fine while driving, but heating up past normal (still not overheating though) when in traffic *outside temps were in the 70s
-- Car started to stutter and buck in the morning but seemed to come back to normal when it warmed up
- Drove the car back from the 3 hour trip and it seemed to be fine
-- Same thing with the temps (hot when in traffic but very good when not)
- Next morning car sounded very strange when I drove it to work (completely different exhaust note, almost like it was missing power)
-- Got to work and something smelled like it was burning (not plastic but almost like metal, very strange)
-- Took the car home after I let it cool down for about 2 hours
-- Same smell when I got home so I drove my other car back to work
- Called a local shop to see if they can check it out
-- Tried to start it and it while it started right up, it immediately died and wouldn't start again after that
- Pulled the PCM fuse and it was blown
-- Changed it out and it still won't start

Here are the relevant mods on the car:
- SVS Stage 1 NA (headers, cams, 70mm throttle bodies, etc..) - no pcm upgrade
- Ron Davis radiator
- Updated fan
- Mopar plug wires with stock plugs (about 11 months old)

WTH is going on here? Did my PCM blow up too? If so, was it possibly a short in the wires somewhere? This car has been having issues for the entire summer and I just want it to be back to the way it was. Killing me here!!

Any help would be appreciated.

- Ron (cornfish)

 

[Asp Man]

Sounds to me like more than one problem. Start with the basics, batt voltage, loose and or corroded conections, etc. Do you have a service manual, or one you could borrow?

The idle hang and poor drivability could be a number of things; idle air motor (that's what I'd suspect first as I had a similar condition, cleaned it and never had the problem again) dirty, worn or faulty. This may have something to do with the PCM fuse blowing, too.
Check for poor grounds on sensor circuits, (coolant temp, idle position, CPS, MAP, etc) this could cause idle issues, and possible contribute to the fuse thing, too.
The over heating; you've taken the air out of the system, so we can assume it's not that. My car allways ran a bit hotter with the Ron Davis rad, which eventualy I replaced with an NOS rad and it's been good since. If there is some underlying problem with the PCM, causing the motor to run lean, would contribute to it's running hot, and if it's in the idle circuit, closed loop, it would seem to make sense.

Don't know if any of this will help, sometimes it helps just to get a fresh pair of eyes on the problem. Take a deep breath and start with the basics, run down things one at a time and go from there.

 

[99 R/T 10]

That is pretty weird, my first call would be to Chuck Tator. 914-763-3136.

 

[cornfish]

Sounds to me like more than one problem. Start with the basics, batt voltage, loose and or corroded conections, etc. Do you have a service manual, or one you could borrow?

The idle hang and poor drivability could be a number of things; idle air motor (that's what I'd suspect first as I had a similar condition, cleaned it and never had the problem again) dirty, worn or faulty. This may have something to do with the PCM fuse blowing, too.
Check for poor grounds on sensor circuits, (coolant temp, idle position, CPS, MAP, etc) this could cause idle issues, and possible contribute to the fuse thing, too.
The over heating; you've taken the air out of the system, so we can assume it's not that. My car allways ran a bit hotter with the Ron Davis rad, which eventualy I replaced with an NOS rad and it's been good since. If there is some underlying problem with the PCM, causing the motor to run lean, would contribute to it's running hot, and if it's in the idle circuit, closed loop, it would seem to make sense.

Don't know if any of this will help, sometimes it helps just to get a fresh pair of eyes on the problem. Take a deep breath and start with the basics, run down things one at a time and go from there.

Hey Asp,

I do have a service manual. At this point, I can't live without it

I forgot to mention the biggest thing, which is that the car only has 17k miles. I just really want to get my car started so I can take it to a shop. Towing always weirds me out because of the damage that can happen while towing on a flatbed.

That is pretty weird, my first call would be to Chuck Tator. 914-763-3136.

I will definitely give him a call. At this point, I will do almost anything to get this thing back up to perfect condition.

 

[ViperGeorge]

I'm not an expert but this is what I would suggest. Check for codes using an OBD reader. Port is under dash on driver's side. Mine is to the left of the steering wheel. Code reader is cheap at any of the parts stores or Sears. I have no idea though if you could even read the codes off of a blown PCM if that is what the problem is but this should be your first step.

I assume the car cranks but no longer starts. If that is the case did you check that you have spark? An inductive timing light would work for this (attach the inductive pickup to a wire and crank, timing light should light every time that cylinder gets spark) or you could do it the old fashioned way - pull a wire and stick an insulated screwdriver in the end put the screwdriver metal part near a ground while cranking see if you have a spark jump across the gap between the screwdriver and the ground. Careful though if you touch the metal part of the screwdriver you will light up your life. If you don't have spark then its ignition related, if you do it may be fuel related.

Do you hear the fuel pump prime when you turn the key on? Check fuel pump relay. Your pump or relay may have given up the ghost. On my 06 there is a port on the passenger side fuel rail for attaching a fuel pressure gauge. Do you have this port? If so buy a fuel pressure gauge from NAPA or one of the parts stores, attach it, crank the car and see if you have pressure. No pressure? Fuel issue. A PCM issue could cause either an ignition or fuel problem I think so that could still be the problem and I would check both ignition and fuel. If the car fails both tests I would think PCM. If it fails one but not the other you would need to further diagnose the failed system, although the PCM could still be the culprit.

 

[dave6666]

What cats do you have? That smell sounds fishy - no pun intended. Can you pull your sills and take a look at what may be smoldering metal heat shields/cats/etc? Although as stated above a lean condition - contributing to the overheating, I agree with that statement - would not overwork the cats, there may be a tune condition that has caused some weirdness. I would certainly want to know the source of that smell. Also, what about your fuel filter/fuel pressure?

 

[plumcrazy]

im wondering about the cats as well. might be plugged ? but a call into chuck tator would be a wise choice to start with.

i just noticed that SVS had a hand in that car possibly....that scares me too

 

[cornfish]

Ok, we just pulled a plug wire and no spark. The other strange thing is that when they key is turned all the way, the fan comes on. This isn't normal right? I could swear the fan only came on when either the AC is turned on or when the car is up to temp.

 

[ViperGeorge]

Did you check for any codes? And did you check more than one wire? If there is no spark then it would seem you have an ignition or PCM problem. I would still check for codes and fuel pressure as well.

 

[cyaford]

What about checking any wiring that is near the headers? I've read about Vipers having weird issues that resulted from aftermarket headers burning through electrical wires.

 

[cornfish]

Another update**

2 of the fuses were blown - PCM and ASD. Replaced both, go to try and start it and the PCM fuse blows again, immediately. Short in the line somewhere?

@Cayford - I am going to jack the car up and check. That fuse blowing scares me.

 

[cornfish]

Yet another update**

Narrowed it down to the upstream O2 sensors - just like Cayford thought (wires near the headers). Unplugged both sensors and no more blowing fuses. Keep you guys updated as we get further into what is going on.

 

[cornfish]

Car is RUNNING now - with no codes. Still having the power/sound issues but I think this might be because of the passenger side O2 sensor, which I must have fried.

There were some nicks in the O2 wires and the heat shrink that I put over it must have been what melted since the wires were all clumped together. Those nicks must have been touching each other and causing a short.

For the short term, I just taped the crap out of it (each wire) until I can order a new sensor from DC performance. Once that gets here, I will see if that fixes the sound/power issues. If not, I am calling Tator.

I am also going to order a new lower temp thermostat to try and help out with the radiator.

Thanks for the replies and if anyone has any more ideas, let me know.

 

[dave6666]

I am also going to order a new lower temp thermostat to try and help out with the radiator.

If you have an overheating problem a lower temp stat won't solve it. All the stat does is determine the starting point at which the coolant starts to circulate. If your car runs at 220*, then guess what... A 160, 170, 180, 195... All of them will be open at 220 degrees.

You need to first find the problem that is making your engine run hot. From there, once it is able to cool itself, a lower stat will lower your operating temp. Which I have read more than once the PCM may not like stats below 180. Too cold.