93 LX Randomly dies while driving but electrical system stays on??

5894 Views 16 Replies 6 Participants Last post by mrstang935050, 29 d ago

935.slow

Discussion Starter · May 29, 2013

So I've been chasing this problem for a while now. I'll just be driving and all of a sudden the rpms drop to zero and I've got no spark. All electrical system still on. If I leave it in gear and cycle the key it picks up where it left off. Like nothing happened. Sometimes it doesn't kill car completely but runs rich for a little bit because of the fuel that wasn't burned when it hiccuped. Timing is 10° with SCT 4 bank trick flow top end and bolt ons.

I've dumped the codes. Changed the distributor, tfi, ignition switch, IAC, Tps, upper and lower intake gaskets checked grounds checked vac leaks, I'm hoping you guys can point me in the right direction. I need to do the coil and 02 sensors but not sure where this prob could be coming from.

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fb93

· #2 · May 29, 2013

The PIP sensor was my first guess but you replaced the dizzy. BUT, what brand distributor? Is it a rebuild? A lot of them use a generic PIP sensor that can be hit or miss when it comes to reliablility. And what brand TFI? They can be just like the generic PIP sensors. Hit or miss. Did you check your codes again after it cut off the last time? What was the last thing you did before it started doing this? Is there any hesitation before it shuts off or does it just flat out die? Whats your fuel pressure? Does the pump prime every cycle? Lots of questions, but it will help us narrow things down.

If you dont have any PIP or TFI codes, it could be the coil cutting out. I wouldnt rule out the PIP or the TFI just yet tho.

935.slow

Discussion Starter · #3 · May 29, 2013

fb93 said:
The PIP sensor was my first guess but you replaced the dizzy. BUT, what brand distributor? Is it a rebuild? A lot of them use a generic PIP sensor that can be hit or miss when it comes to reliablility. And what brand TFI? They can be just like the generic PIP sensors. Hit or miss. Did you check your codes again after it cut off the last time? What was the last thing you did before it started doing this? Is there any hesitation before it shuts off or does it just flat out die? Whats your fuel pressure? Does the pump prime every cycle? Lots of questions, but it will help us narrow things down.

If you dont have any PIP or TFI codes, it could be the coil cutting out. I wouldnt rule out the PIP or the TFI just yet tho.

Its always done this. I got the car a couple months ago and been trying to chase this thing down. I did use a reman dizzy just to see if the pip was my problem. There was absolutely no change. I believe its a motor craft tfi module. I just did the dizzy yesterday and it cutout twice on the 5 min ride home. Fuel pump is priming everytime pressure set at 39 with vac off. 24lb injectors.

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---------- Post added at 10:23 AM ---------- Previous post was at 09:17 AM ----------

Dumped codes again this morning. Got 15 which says read out failed but then it stil gave me codes? 67 85 29 koeo 21 41 91 KOER. So i ordered MSD coil and new ntk 02 sensors from american musce. But i still think theres something im missing.

narleycarley

· #4 · May 29, 2013

Ignition switch?

My 91 acts funny sometimes when I use my spare key. Very weird.

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935.slow

Discussion Starter · #5 · May 29, 2013

narleycarley said:
Ignition switch?

My 91 acts funny sometimes when I use my spare key. Very weird.

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Just replaced that yesterday :/

fb93

· #6 · May 29, 2013

935.slow said:
Dumped codes again this morning. Got 15 which says read out failed but then it stil gave me codes? 67 85 29 koeo 21 41 91 KOER. So i ordered MSD coil and new ntk 02 sensors from american musce. But i still think theres something im missing.

KOEO codes:

67 -make sure you push in the clutch during the test or this code will pop up. Also make sure the heater and a/c are off. If all that checks out it could be the Neutral Drive Switch (that is on the transmission itself) or its wiring gone bad. The switch at the pedal is the Neutral Safety Switch.

85 - CANP (canister purge) valve circuit failed. Unless you removed it, it is next to the charcoal canister. A line runs from the upper intake to the valve. make sure its hooked up if you still have it.

29 - VSS (Vehicle Speed Sensor) failed. The computer did not receive a signal from the VSS during the test. Clear the codes and take it for a drive. If 29 comes back, check the VSS wiring. If it checks out, replace the VSS.

KOER codes:

21 - ECT (Engine Coolant Temp) sensor. this can pop up if the engine hasnt been properly warmed up for the test. Drive around a bit and do the test again. If 21 comes back, check the wiring. If it checks out replace the ECT.

41 and 91 are both O2 sensor codes. They may be bad or your engine may simply need a tuneup.

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935.slow

Discussion Starter · #7 · May 29, 2013

fb93 said:
KOEO codes:

67 -make sure you push in the clutch during the test or this code will pop up. Also make sure the heater and a/c are off. If all that checks out it could be the Neutral Drive Switch (that is on the transmission itself) or its wiring gone bad. The switch at the pedal is the Neutral Safety Switch.

85 - CANP (canister purge) valve circuit failed. Unless you removed it, it is next to the charcoal canister. A line runs from the upper intake to the valve. make sure its hooked up if you still have it.

29 - VSS (Vehicle Speed Sensor) failed. The computer did not receive a signal from the VSS during the test. Clear the codes and take it for a drive. If 29 comes back, check the VSS wiring. If it checks out, replace the VSS.

KOER codes:

21 - ECT (Engine Coolant Temp) sensor. this can pop up if the engine hasnt been properly warmed up for the test. Drive around a bit and do the test again. If 21 comes back, check the wiring. If it checks out replace the ECT.

41 and 91 are both O2 sensor codes. They may be bad or your engine may simply need a tuneup.

I checked those as well thanks for the reply. Brand new plugs and wires as well as dizzy I dont suspect a tune up is in order. The car wasnt warm so Im sure that why the temp senor code came up because its new as well. Smog and Ac are deleted so my canp code shouldnt matter either.

Where is the vss located? I mean the speedometer works. Its off because of the 4.10 gears but its working. I ordered new O2 sensors this morning to be safe...

fb93

· #8 · May 30, 2013

The VSS is at the oppsite end of the speedo cable. Come to think of it, the VSS can cause stalling if its not working properly, or disconnected on MAF cars. The speedometer may work but if the computer isnt getting a signal from the VSS, the engine will usually stall as the computer thinks youre not moving so it adjusts the air/fuel based on that incorrect VSS signal. So that right there could be your problem.

The VSS i believe takes an 11mm socket?

935.slow

Discussion Starter · #9 · May 30, 2013

fb93 said:
The VSS is at the oppsite end of the speedo cable. Come to think of it, the VSS can cause stalling if its not working properly, or disconnected on MAF cars. The speedometer may work but if the computer isnt getting a signal from the VSS, the engine will usually stall as the computer thinks youre not moving so it adjusts the air/fuel based on that incorrect VSS signal. So that right there could be your problem.

The VSS i believe takes an 11mm socket?

So at the tranny? Or follow the cable up. I was actually lookin for it before you said something! I got under there and saw the cable on the tranny(5spd) but then I got busy at the shop.

935.slow

Discussion Starter · #10 · Jun 6, 2013

So ive installed the new msd coil and NTK O2 sensors. There was once again no change. I cant tell if its losing spark or randomly flooding itself out. My wideband goes rich Maxes at 10 and sometimes it does sometimes it revocers itself. Even at idle after a while it will hiccup I look down and my A/F is slowly leaning back out from 11-16 like it restarted the enrichment process.

I still have to change vss which I already have just havent installed it yet. This thing is killin me. I dont think its in the tune. bur I sure dont want to spend the money on a dyno when I could have the exact same problem. Any ideas on where to go next?

Computer maybe?

cookiewhistle

· #11 · Jun 7, 2013

Have you checked your plugs at all since this started? I'd check them to see if they're doused in fuel. Also are you still running the stock MAF? Someone correct me if I'm wrong but IIRC the factory MAF doesn't like to run with 24lb injectors (unless it's a Cobra MAF).

onebadstanger

· #12 · Jun 7, 2013

you are right if you change the injectors u also need to change the maf to match

cookiewhistle

· #13 · Jun 7, 2013

In that case, then I'd cruise craiglist for a calibrated MAF or see if there isn't someone near by that you can borrow. That might end up being your problem if it's the factory MAF.

935.slow

Discussion Starter · #14 · Jun 25, 2013

Turns out it was the ecu. After O2 sensors tps iac plugs wires fuel pump pcv coil tfi distributor intake and tb gaskets. Everything. It was the computer. Lame

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---------- Post added at 09:16 PM ---------- Previous post was at 09:15 PM ----------

cookiewhistle said:
Have you checked your plugs at all since this started? I'd check them to see if they're doused in fuel. Also are you still running the stock MAF? Someone correct me if I'm wrong but IIRC the factory MAF doesn't like to run with 24lb injectors (unless it's a Cobra MAF).

It was bbk cold air with bbk maf and 24#ers on bama tune. Thanks for the suggestion though

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cookiewhistle

· #15 · Jun 25, 2013

Glad you got it all figured out. At least you have a bunch of new parts on it now though!

935.slow

Discussion Starter · #16 · Jun 25, 2013

cookiewhistle said:
Glad you got it all figured out. At least you have a bunch of new parts on it now though!

Right. Thats what I kept telling my self. You dont know how old these things are might as well change/upgrade them. Now I can soend money makin her faster Instead of consistent. Woohooo

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mrstang935050

· #17 · 29 d ago

935.slow said:
So I've been chasing this problem for a while now. I'll just be driving and all of a sudden the rpms drop to zero and I've got no spark. All electrical system still on. If I leave it in gear and cycle the key it picks up where it left off. Like nothing happened. Sometimes it doesn't kill car completely but runs rich for a little bit because of the fuel that wasn't burned when it hiccuped. Timing is 10° with SCT 4 bank trick flow top end and bolt ons.

I've dumped the codes. Changed the distributor, tfi, ignition switch, IAC, Tps, upper and lower intake gaskets checked grounds checked vac leaks, I'm hoping you guys can point me in the right direction. I need to do the coil and 02 sensors but not sure where this prob could be coming from.

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Hi, I have the exact same problem with my 93 and I don’t know where to start to figure it out. Did you end up finding your probl…? If so can you let me know please. Thanks

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