Need some help...boost/driving issues

[Bubba]

Last weekend I was having some problems with idle getting stuck at 2k rpm after driving on the highway for a while, then in park, it would bounce up and down(surge). All of my vacuum lines were original for the most part, so thinking it was a vacuum/IAS/TPS problem. I delted all of the original vacuum lines and using a vacuum blokc I ran only the necessities, i.e. MAP, FPR, BOV, boost gauge etc... Then as soon as I get into boost, it falls on it's face bucking etc.. almost like cut-out. I replaced the tps and ais, same issue, car wouldn't run under it's own power, almost died by giving just a little bit of gas. I re-checked ignition/valve timing all is fine (thought maybe my cam jumped a tooth, but didn't). I checked fuel pressure while brake torquing, it was fine and didn't fall off. I found a loose distributer cap, swapped that out, the HEP, MAP and MAP solinoid. All this time I'm not getting any codes. In fear of breaking down on the road, I would break torque at a stand still to get into the boost and wait for the fumble. After all of this I reset the SBEC, brake torqued and still had the samer problem. I pulled the car out of the garage and turned it around and backed it in. Just for the heck of it, I brake torqued again and the problem's gone...what the heck? Now it's doing like it should. The only thing left is the speed/distance sensor? That was replaced last summer with a new one.

Sorry for the lengthy post, but I didn't want to leave anything out. I've got 2 weeks til' the Dyno day and gotta get this figured out6. Thanks!

[GLHSKEN]

Check the AIS. or tps. Often times they are the culprit but the TPS throws the cods.

[Bubba]

Both were changed.

[inmyshadow]

As for falling flat on your face as you hit boost. I'd check the fuel injection wiring. The pins in the connectors might have come loose.

I had that happen on my last shadow. I could jiggle that harness and the car would stall. Sometimes, as I hit boost, the car would buck. Probably from the wiring harness being moved around.

later

[Bubba]

As for falling flat on your face as you hit boost. I'd check the fuel injection wiring. The pins in the connectors might have come loose.

I had that happen on my last shadow. I could jiggle that harness and the car would stall. Sometimes, as I hit boost, the car would buck. Probably from the wiring harness being moved around.

later


Yea, that's one thing I haven't looked at.

[Bubba]

I looked at the injector plugs and they're tight. last Summer I had tore the injector harness apart to inspect etc... and everything looked good.

[inmyshadow]

I'm talking about the connector between the engine harness and fuel injection harness.

There is usually a plastic piece in the middle of the female connector. I pulled out that little plastic piece. Then I used pliers to squeeze to tighten up the female pins.

I've done the same to my speed sensor too.

Never had the problems again.


I looked at the injector plugs and they're tight. last Summer I had tore the injector harness apart to inspect etc... and everything looked good.

[Bubba]

I'm talking about the connector between the engine harness and fuel injection harness.

There is usually a plastic piece in the middle of the female connector. I pulled out that little plastic piece. Then I used pliers to squeeze to tighten up the female pins.

I've done the same to my speed sensor too.

Never had the problems again.

I can look into that a bit to be sure. I'm fixin' to take it out around the block to see if it runs any better.

[Bubba]

The injector harness and main plug looks fine. Get this...I took it down the road and back and it drove great...no problems. I get back to the house and check ignition timing, thing starts running like poo. I can hold the gas at 3k rpm and it's really rough sounding. I swapped out the tps for another one I had laying around and I've still got the same problem. I'm starting to wonder if I got some bad gas and my filter got clogged or something stupid like that. I had a new fuel filter, I guess I can put it on and see if anything changes.

[Bubba]

code 13

[85_600]

code 13

Are you thinking the "Pin hole Leak in the FPR"?

http://minimopar.knizefamily.net/fault/code13.html

[Bubba]

Are you thinking the "Pin hole Leak in the FPR"?

http://minimopar.knizefamily.net/fault/code13.html


I got it to act up and while it was acting up it threw a code 13. I plugged the MAP sensor directly to the intake manifold and it runs fine. I had replaced the solinoid and MAP earlier today, so the only thing that makes sense is a vacuum leak from the solinoid to the sensor itself or a wiring problem to the solinoid possibly. I checked the vacuum line from the solinoid to the MAP and it seemed fine, but wasn't zip-tied, so could've had a vacuum leak to the MAP. I'll investigate a bit more tomorrow if I can to determine the exact cause of this. The intermittent nature of this problem makes me think that it wasn't a vacuum leak. Can the MAP sensor be ran without using the solinoid?

[Bubba]

Stupid car. To eliminate the solinoid as the problem, I ran the MAP directly to vacuum and went for a drive. For one, it still cuts out after getting into boost and sometimes it stalls out. I'm at wits end with this problem. I checked my FPR line again for gas being in it and that's not the case. It smells a bit like gas, but the cars been running really rich since the MAP problem it seems.

[Bubba]

Somebody brought up a good point. The previous owner had a zener diode to cheap MAP cut-out, could this bee my problem all along?

[Bubba]

I'm out of ideas. I took the zener diode out and only got to mess with it for a few minutes, but it didn't seem to change anything. I just don't get what could've went so wrong so fast, it was running pretty darn good and now nothing but crap.

[Keito]

Spark blow out?
Are you coming to the meeting tomorrow?

[Bubba]

Spark blow out?
Are you coming to the meeting tomorrow?

I just posted on the buckeyesdac page. I'm not gonna make it tomorrow....I gotta work at 1pm and the cars all messed up.


As far as spark blow-out....I don't think so, they're actually gapped at .029 a bit closer than stock, so blow-out shouldn't be a problem and they're fairly new maybe 100 or so mile NGK equivalent to RN9YC Champions. At this point I'm gonna end up missing out on the dyno day in 2 weeks if I can't come up with answers quick as to what's wrong.

[Dave]

Christian... you have to trace problems down to their origin. It ran great, you messed with the vacs. and it got screwed up. Do you have all your lines going directly to the block? Each line in it's own individual plug with no teeing whatsoever?

Of course it wont run without the barometric solenoid being plugged into the MAP. Both need eachother to keep in check.

Code 13 (MAP) could be anything like I told you last week, TPS or AIS. Okay you replaced those and the problem's still there. It's MAP related, but you also eliminated the MAP sensor itself. Did you ever change the baro. solenoids? I know '91's run off the 4 on the passenger side instead of just one. It's vaccum related is my guess. Redo the lines again.

Don't worry man, we'll make sure you'll make it to Dyno Day! :thumb:

[Bubba]

Christian... you have to trace problems down to their origin. It ran great, you messed with the vacs. and it got screwed up. Do you have all your lines going directly to the block? Each line in it's own individual plug with no teeing whatsoever?

Of course it wont run without the barometric solenoid being plugged into the MAP. Both need eachother to keep in check.

Code 13 (MAP) could be anything like I told you last week, TPS or AIS. Okay you replaced those and the problem's still there. It's MAP related, but you also eliminated the MAP sensor itself. Did you ever change the baro. solenoids? I know '91's run off the 4 on the passenger side instead of just one. It's vaccum related is my guess. Redo the lines again.

Don't worry man, we'll make sure you'll make it to Dyno Day! :thumb:

I triple checked all the vacuum lines this morning and I had already swapped the solinoid. Every line is new and zip-tied. I had to rig up the MAP to run since I have the newer style MAP, but only an older style spare.

[Bubba]

I hooked the MAP baro solinoid back up. Changed distributer cap and rotor(they looked a bit' worn, but not too bad). Changed my ignition coil and dressed up some sloppy wiring going to the coil. Reset the SBEC and plugged my charge-air sensor wiring into the harness(not hooked to the sensor yet, current SBEC doesn't use it). Let it idle for an extended period of time, maybe 15 minutes or so. I took her for a drive and it's driving wonderfully again, although it did break-up one time getting into boost on the highway at high gear. I had lowered my fuel pressure a bit, so I raised it back up a couple psi after getting back home. Honestly, I'm not sure what I did to get it to run descent again. I'm using the original MAP sensor and baro solinoid. I'm still concerned about the one time it broke up on the highway...seemed I had enough fuel. Ignition timing is set at 14 degrees and valve timing is advanced about 4 degrees. I'm gonna put the valve timing back to 0 degrees (I had it this way from a while ago when I had some higher EGTs).