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View Full Version : Engine cuts out when warms up



kennyo
08-16-2015, 04:01 PM
I thought I had an egr problem but I forgot I deleted it years ago....When the car gets warm it will die when accelerating. You let off the gas and it will smooth out and run fine. When it happens the tach will drop like there is no voltage getting to it. Could this be a DIS issue, a coil pack or even a crank sensor going bad???I replaced the crank sensor last year... it completely died when that went out..It's not throwing any codes so I'm at a loss as to what it could be...The fuel pressure is in range so I'm thinking it has to be something electrical

KMT
08-16-2015, 04:17 PM
Tach drop is classic cam sensor issue - just remember there can be other maladies involved, from poor grounds, to compromised wiring to additional elect. components. Run the codes before jacking up the radiator cap and spending money.

SuperCoupe007
08-16-2015, 04:28 PM
Sounds like DIS module or camshaft sensor.
I also agree with KMT

kennyo
08-16-2015, 06:23 PM
Sounds like DIS module or camshaft sensor.
I also agree with KMT

Well it wasn't the cam sensor, had to order a DIS module. Hope that fixes it.

KMT
08-16-2015, 06:31 PM
...might be a combo of things, so let's hope the DIS does it.

bowez
08-16-2015, 08:34 PM
I wish you luck, one year and counting for me. Still have had time to go deeper with my new position, even old position this is a busy time of year.

kennyo
08-17-2015, 07:43 PM
I have changed out both the DIS and the cam ~~~ sensor... Engine still cuts ou/offt under boost or load The tach quits then it starts up again. There is no way one plug or wire would cause this to completely die like this..... fuel pressure is still good... No codes other than the egr because of the delete....WTH, I'm at a loss. I took it back out after cleaning map sensor. It doesn't buck or cut out it's like the switch was turn off. If I leave it in gear and coast it starts back up and runs fine...... Okay I went out and unsnapped all of the connectors and fuses in the fuse relay box. Took it and ran the hell out of it and now no problem ....damndest thing . We'll see how it does tmrw I guess

KMT
08-17-2015, 09:18 PM
Looking at the upper/front harness that connects the DIS, cam, crank sensors, coil....how would you describe it's condition? Frayed? Oil soaked? Patched together w/butt-splice connectors and black tape?

Is the ground strap off the pass. side motor mount over to the body original?

kennyo
08-18-2015, 08:59 PM
everything looks pretty good. Not sure about that ground strap. The car is a garage kept 160k original mile car......even taking it easy on it the damn thing is always needing something :) Not to bad for a 26 yo car though.

kennyo
08-31-2015, 09:26 PM
update: I've been f'n with this damn thing for a week now. My current situation is it now has a constant upshift light and a code 14. Today is the first time it threw a code, No one ever said whether or not a crank sensor would come and go so I assumed it if it was bad it would not start at all. As of now it is sitting in a no start condition. The search feature finally started workin for me so I will investigate further

KMT
08-31-2015, 10:47 PM
A crank sensor can act out for various reasons, some of which manifest intermittently...but those are usually compound issues where the crank sensor isn't the root cause and may simply be doing it's best under certain conditions, which can include busted balancer, shredded belt, bad grounds, compromised harness, etc.

The point is to check things out very carefully. These cars live/die on grounds, BTW, so if one is suspect/in doubut (and at 160k miles, they all are) don't go on looks alone - replace it. Corrosion can hide inside the sheath and/or the mount point, raising resistance out of spec. And then there is EMI to deal with...

kennyo
09-01-2015, 01:45 PM
What is an EMI??

KMT
09-01-2015, 02:07 PM
Google says emi means 'electromagnetic interference (http://searchmobilecomputing.techtarget.com/definition/electromagnetic-interference)' - with the heavy use of electronics on an SC, Ford helped reduce random signals that might interfere with various inputs by shielding certain wires (wrapped in foil, then taped, etc.). If the factory shielding is compromised, there is a chance that what started out as a valid signal may be changed or caused to drop completely. The effect can be misinterpreted as a faulty sensor, when actually, the wiring is the culprit.

kennyo
09-01-2015, 02:37 PM
Google says emi means 'electromagnetic interference (http://searchmobilecomputing.techtarget.com/definition/electromagnetic-interference)' - with the heavy use of electronics on an SC, Ford helped reduce random signals that might interfere with various inputs by shielding certain wires (wrapped in foil, then taped, etc.). If the factory shielding is compromised, there is a chance that what started out as a valid signal may be changed or caused to drop completely. The effect can be misinterpreted as a faulty sensor, when actually, the wiring is the culprit.


Thanks, I hope you know us rookies appreciate your input. I did figure one thing out today... A couple of years ago I lost signal to my ac comp and fans. I couldn't figure it out so I made a mini harness to to correct that problem... Well 2 years later I stumble upon the ol IRCM thread. Could this be jacking with me also on the other issues??

Mike Puckett
09-01-2015, 03:03 PM
A few years ago my old 35th developed a stumbling, wouldn't run good, kept trying to stall condition. It turned out to be the supercharger belt was rubbing on the wire bundle and rubbed a hole in the insulation on one wire. Well, you wouldn't think that a rubber belt rubbing on a wire would cause a problem but it did. I suspect static electricity which I've seen do strange things to electronics was being generated by the belt and would discharge into the bare spot on the wire. I've also had problems where it would idle fine but not rev. It would just die out. That turned out to be the TPS sensor not sending a voltage back to the EEC telling it that the throttle was opening up. I've also had intake and IC tubing leaks that would make the engine stumble, stall, and not want to warm start.

KMT
09-01-2015, 03:50 PM
Could this be jacking with me also on the other issues??

Not sure if it would be having a direct effect, but it could a hinting at other/related issues. These cars are all getting up there in years, which means gremlins such as corrosion, EMI, bad grounds, borked balancers, etc. are more likely to surface.

Point is to not get too creative, avoid used parts (sensors as an example) wherever possible (when working w/used parts, have more than one spare to test with) and work the issue, being sure to not take steps without cause or you'll just tail-cha$e. Issues like yours have solutions, and I feel the pain of anyone trying to sort them out, but it takes a specific awareness of the care these cars and patience to work logically (make notes if that helps) when it comes time to open the hood. Stick w/it, don't let it get to you and good luck.

kennyo
09-01-2015, 05:32 PM
I'll get eventually.... I've fixed and replaced everything as soon as it goes bad. Keep it clean and garaged. I forget it's 26 years old sometimes...My first car was a57 Skyliner and it was only 19 years old :)

kennyo
09-01-2015, 09:03 PM
well it was the one year old balancer I bought when the CS went out last year. It came apart and snapped the bolt off in my crank.. So it must have been the bolt broke and was sliding in and out. I'm glad I found a concrete problem but I'm screwed if I can't get the rest of the bolt out. Any bolt removal tips:)

KMT
09-01-2015, 10:27 PM
Any bolt removal tips:)


Might depend on what's left - any photos?

Should be several threads here on the topic - some recent. Search is your friend, but yell if you strike out.