Intermittent engine shutdown

[tgraves2]

I have an '87 with a 2.9. When I first acquired the truck it would not start on occasion. When I finally got it to where it would start and run consistently, I had replaced the coil, distributor and module, wires and plugs, fpr (they were all old anyway).
About two weeks ago it started to cut out while driving. It felt like running over a small stick or something, kind of like a thump, but sometimes would start right back and not miss a beat; other times it will not start for several minutes or hours. I have checked ground wires as best I can and all seem OK.
A friend said her Nissan was doing something similar and was diagnosed as a crankshaft sensor. Does my 2.9 have one? Could it be that?
I am planning to try to pull some codes; can it be done with a test light instead of the analog multimeter? Any help would be greatly appreciated as I drive 42 miles one way to work and sometimes have to open the store which means I have people depending on me to be there. I really do not have a lot of confidence in my truck at this time.
Any help would be appreciated.

 

[RustedRanger]

No crank sensor. The tech section here at TRS explains how to get the codes with a test light. I had a similar problem and replaced many,many parts and found out the coil was weak but I see yours is new but my friend that helped me found that the plug-in to the coil was bad also. Try moving the plug-in around while its running and see if that causes it to miss more.

 

[JAB]

I had a similar problem on my '88. It turned out to be a fuseable link in the engine harness. Do a wiggle test on the harness on the drivers side. I found my problem around the steering box if I remember. The wires just work hardened and/or corroded and one by one broke and finally disconnected. Please post back when you find it. Good luck.

 

[tgraves2]

Thanks so much for the info. When it quits raining I'll try the "wiggle" test. The wires are old I think, but it sure didn't sink in to try wiggling them!? Kind of a 'duh' moment here. Thanks again. I will get back with you when I get a chance to check it out.

 

[freerider6_9]

sounds simmilar to the problem i was having. try hooking up a fuel pressure guage and have it somewhere you can see it while driving and when it has its little fit see if your FP is dropping intermittently

 

[tgraves2]

I tried wiggling the wires and think I have a loose one or cracked one. The engine didn't die, but it did rev up for a second or two then idled down. Did this twice when I wiggled the wires, but couldn't get it to do it again. Can you tell if a fusible link is bad by looking or feeling it?

 

[IMenriched]

I tried wiggling the wires and think I have a loose one or cracked one. The engine didn't die, but it did rev up for a second or two then idled down. Did this twice when I wiggled the wires, but couldn't get it to do it again. Can you tell if a fusible link is bad by looking or feeling it?

Usually it just cuts out from the change in continuity. but certainly could not hurt to go through and make sure the battery cables are all good as well as the grounds. as far as just looking at it & telling if it is bad, doubt it unless it is hot to the touch. or severly bulged/ corroeded

considering it rev'd up...it be wise to double check the vacuum lines.

getting codes is a step in the right direction

 

[tgraves2]

Thanks for the input. Can't seem to find the test plug. I've looked on both sides of the engine compartment and by the e brake inside. Probably just looking right past it. Vacuum lines seem to be OK. It seems to be running OK again. I supported the wire bundle on the drivers side. Did find the the smaller black wire from the neg terminal of the battery is bare in a few spots from a bad starter. Planning to fix that soon hopefully.
I have read in the forum (excellent resource by the way) about moving the TFI module from the distributor to a "cooler" spot. How would one go about that? Is there a cable you can get to do this? I would like to move mine if possible, but I am not a real good electrician. This wire chasing drives me nuts!

 

[IMenriched]

Thanks for the input. Can't seem to find the test plug. I've looked on both sides of the engine compartment and by the e brake inside. Probably just looking right past it. Vacuum lines seem to be OK. It seems to be running OK again. I supported the wire bundle on the drivers side. Did find the the smaller black wire from the neg terminal of the battery is bare in a few spots from a bad starter. Planning to fix that soon hopefully.
I have read in the forum (excellent resource by the way) about moving the TFI module from the distributor to a "cooler" spot. How would one go about that? Is there a cable you can get to do this? I would like to move mine if possible, but I am not a real good electrician. This wire chasing drives me nuts!

the diagnosis port or plug maybe hidden a bit, for sure. Usually it is on the passenger side , between the air filter box and firewall. Sometimes it gets tucked in behind the air filter box and the fender.

yes the tech library (see above tab) is a very good source of info. in there you'll find how to retrieve codes.

 

[tgraves2]

Sorry it took so long to reply. I did find the test plug and it was DEFINITELY hidden. It was tucked in under the fan housing between it and the air inlet housing; like I said I looked right past it.
It had been running well again, but the other day it wouldn't start after parking it for a while. Cranks over fine, but no fire. The next morning it fired up but died after about 15 seconds like it ran out of gas. I pulled the gas line and turned the key on and it only went about 4 inches straight up. I replaced the inline fuel pump since the one on there was original i think. Still only fires occaisionally and for a short duration.
I tried to pull codes according to the tech section, but all I got from the meter was a reading of 12v or so. No sweeps or anything. I am really confused. I really like this truck, but coming close to shooting it.
I really appreciate all the help so far; anymore ideas?

 

[IMenriched]

not completely sure what is all involved in "moving the TFI"...but I know its been done. sorry not much help there.

chasing wiring issues can be a ball of frustration...no doubt. Appears your kinda back to square 1.

are you certain of what is missing....spark or fuel?? be sure your battery is fully charged.

just to cover your bases....remove and have the TFI rechecked...make sure it is good...most parts stores will check these for free...be sure to have it checked min of 3-4 times.


While it is off (the TFI)....look under side of the distributor and make sure the connection the TFI is going into isn't crusty or half burnt or anything and connections are firm and not misplaced/ misaligned ...might need the help of a mirror and well aimed flash light for this.


be sure to apply the dielectric compound/grease to the mating surfaces of the TFI when going back together...a bit across the spade connections too, this helps seal out heat and moisture.

sorry i reread and realize it a fair drive to the parts store.
Pull a plug and wire....turn it over, with help of a buddy, to see if it has spark visible, while plug is attached to the wire and carefully holding plug as to see against the exhaust manifold. should be able to see the spark.

If it's turning over nice and healthy....disconnect the air hose by the throttle body.

get a buddy to help....draw straws er something to see how is going to turn the key.
as one tries to start it...the other spray a 1-2 second blast of either/starting fluid directly in front of the throttle body....if it starts and runs briefly then it is missing fuel....if not then it is missing spark.

from the sounds of it..fuel is what is still missing. even though it appears that you have good fuel pressure...."squirting out 4"....it still might not be getting delivered to the cylinders

Id check the connection to the fuel pump relay...(Located again Passenger side fender, about the size of a ice cube). check those connections sometimes the pin/spade will push back as one engages contact. these relay are relatively inexpensive ...had one that was bad on inside....with help of a buddy, I tapped on it (the relay) with my finger as the engine was being turned over, all of a sudden it started. these relays are sealed but units but as with anything are not immunized from going bad.

also check the inertia switch...inside the cab , Passenger side, near where your left foot would rest. see if current is passing through it...1st try the reset button on top. If no power incoming to the inertia switch then back towards the relay looking for bad wire/connection.

 

[tgraves2]

Thanks IMenRiched. Will try to do the spark test this afternoon. Just have a nagging feeling it is fuel since it starts off and on. Will definitely have have to put the battery on the charger; I noticed it was turning slow last time I tried to start it. (Had been cranking it off and on for a while). Will also have to do the spark check as well. This is an old truck and had been well used when I got it. Probably have put too much into it, but for some reason I really like this truck, despite the bad paint and body cancer. I really appreciate the help from you and all the others in tis forum.

 

[tgraves2]

A mechanic friend came by and pulled codes for me. Showed a bad TPS and temp gauge sensor. Seems to be working now. Will hold my breath for a while and see if it is REALLY fixed. Anyway, seems to be good to go at this point. I REALLY appreciate all your input on this!