Engine cutting out

Newps

 
 
Joined
May 24, 2004
Messages
1,540
Location
Huntington Beach, CA
1994 LC 80 with 142,600.

Changed the oil & oil filter yesterday, gave her a wash and hosed down the engine compartment. Did not pressure wash or spray engine hard, just a good rinsing with the nozzle at gentle shower.

Drove car after wash, ran fine. Drove car this morning about 10 miles came home to pick something up and was heading out to work. Engine cuts out when I hit 35 to 40 mph, back off it comes back, gas it again it cuts out, this now happens when every I hit 35 to 40 mph. If I am really gentle with the accelerator I can get it up to speed say 60 but if I get on gas at all it cuts out.

Here what I have done:
1. Searched Ih8mud, one guy traveling from Houston to Austin had the similar problem but it only happed to him when he hit a bump, that tread unfortunately stopped before a fix was posted.
2. Checked fuse box on drive side engine, fine no water, no blown fuses
3. Checked distributor, no water.
4. Pulled hose between engine and air filter, no cracks hose and bellows.
5. Checked all connections around the area of oil filter, thought maybe I knocked one off during the change. Everything looks fine.
6. Checked codes, got a code 83, C-Dan said that was a non-issue with the problem I am having.

The only thing I have figures out, truck runs fine for about 15 to 20 minutes, I can stand on it as hard as I want with no problems, then after 15 to 20 minutes engine starts cutting out past the 35 to 40 mph mark. Anyone out there had a problem like this?
 
Joined
Nov 16, 2003
Messages
6,045
Location
Dixie co. Florida
search for fuel pump relay, cutting out at higher throttle positions is one symptom, mine acted exactly as you say, step on the gas and it cuts out complete loss of power, let off the gas and it runs just fine,

Does it ever have any trouble starting, long cranks but no fire? That is the other symptom of problems in the high voltage side of the relay.

Several people have had problems with it. The relay is expensive so try cleaning it first (search for instructions with pictures)
 

Newps

 
 
Joined
May 24, 2004
Messages
1,540
Location
Huntington Beach, CA
Raven Tai, that sounds like my problem. Question, anyone know where is the fuel pump relay on a 94? I check every thread with fuel pump relay in it, no pictures of one.
 

Newps

 
 
Joined
May 24, 2004
Messages
1,540
Location
Huntington Beach, CA
Thanks landtank, I read you thread on cleaning the fuel pump relay. Unfortunately I cannot find the relay, I have not yet bought the service manual for my truck. Do you know where it is on a 1994 80 and what it looks like?
 

Newps

 
 
Joined
May 24, 2004
Messages
1,540
Location
Huntington Beach, CA
Update…. cleaned fuel pump relay, did not fix the problem, it actually made it worse. Instead of running fine for 15 minutes it now has the sane problems right away. I figured since I messed with the relay and now the problem happens right away, it must be a bad fuel pump relay.

Installed new fuel pump relay today, did not fix the problem. Engine still cuts out if I get on the gas hard or go faster then 40 mph.

Back to square one, any one else want to chime in?
 

semlin

curmudgeon
 
 
Joined
Mar 27, 2003
Messages
5,345
Location
north of 49
-fuel pressure regulator also springs to mind. There is a test you can do just by removing the vacuum hose and working the throttle.

-considering the trouble started after you washed it I would pull the plugs and inspect them and the plug leads to be sure.

-Then I would start tracing the fuel relay wiring for continuity and corroded connections
 
Joined
Mar 16, 2005
Messages
24
I think I may know what the problem is! This exact thing happened to my brother's '94 LC after he washed the engine. First, of course, check to make sure there is no water around the spark plugs. (that wasn't it for me though) It's been awhile since I looked at his engine, but I found water inside one of the electrical plugs that is attached to the intake. once this was blown out, all was good. If you are standing in front of the car, the plug is facing left (meaning if you pull on it to disconnect it, it would pull apart towards the passenger side), attached to the throttle body, and it is not straight up-and-down, but turned at an angle. I believe it was gray in color, but I can't be sure. There was just a little bit of water in there, and my guess is that it was creating a connection between two or three of the prongs in there.....good luck, I hope this helps! If you need a better description, let me know......

Chris
 

Newps

 
 
Joined
May 24, 2004
Messages
1,540
Location
Huntington Beach, CA
CS888 rookie steps up big time!! Problem solved, took off the connector described above and sprayed some compressed air in and walla, truck runs again! Thanks a bunch, Chris e-mail me your address, some cool sh*t is coming your way.
 

semlin

curmudgeon
 
 
Joined
Mar 27, 2003
Messages
5,345
Location
north of 49
nice catch chris. i like happy endings. I believe that you are describing the harness for the TPS on the throttle body.
 

landtank

SILVER Star
 
 
Joined
Mar 27, 2003
Messages
19,670
Location
Groveland MA
if there was water in there, that connector has issues. All the connectors under there as gasketed. You can get a new housing which is probably your problem as it's most likely cracked.
 

Newps

 
 
Joined
May 24, 2004
Messages
1,540
Location
Huntington Beach, CA
It was really a small amount but it was all it needed to cause the problem. Drove it again today, no issues what so ever. I will look at the housing today in the sunlight and see if it's cracked. I doubt it’s cracked though, it just does not seal that well. A little electrical tape will fix that though.
 
Joined
Nov 16, 2003
Messages
6,045
Location
Dixie co. Florida
electrical tape will not hold up long under the hood, dielectric grease would be better for keeping water out of the connection. but you dont want grease to get into the TSP though.
 

landtank

SILVER Star
 
 
Joined
Mar 27, 2003
Messages
19,670
Location
Groveland MA
the housing is like the cost of a good roll of tape and easy to install. I know as I broke the locking tab off of that one myself. You need to realise that there is an inner gasket that seals the connectors from the elements as well as the wires entering the rear of the housing. Why mickey mouse a beautifully engineered connector.
 

Newps

 
 
Joined
May 24, 2004
Messages
1,540
Location
Huntington Beach, CA
I will check and make sure that gasket is in there, I did notice that there is nothing protection the rear of the housing where the wires run in. Maybe this is how the water got in? I was just going to wrap the junction between the two pieces with some electrical tape pulled really tight. I figured this would just be a little insurance.
 
Top Bottom