Engine dies coming to a stop...

[axolotl81]

I have a 94 80 with no mods. The problem I am having is when I get the 80 up to 55 to 60 mph when and then I come to a stop the engine dies. It does it every time I get up to at least 55 mph and as I slow the truck to come to a stop I notice the rpms drop quickly when I am almost completely stopped. The engine also tends to almost die when coming to complete stops at normal city driving.

Not to sure what to look into. Anybody heard of this and might know how to fix it? Its getting annoying when my engine keeps cutting out at stops off the freeway. Any help is much appreciated. Thanks.

Clint

 

[beachcomberspi]

IACV may need cleaning?

 

[BlackLS1]

the dashpot controls the butterfly valve from closing too fast. its under the throttle body and should be spring loaded. the procedures for checking it is in the FSM

 

[JCruse]

I had two cars that died at every light or stop sign if you didn't keep your foot on the gas. It was the Mass Air Flow sensor in both cases. I don't know if a '94 has a MAF though.

 

[bajaphile]

I vote idle air control valve sticking as well. Test your MAF or volumetric air flow meter as well. Are you sure that the check engine light bulb is working?

 

[tomcat]

I have a 94 80 with no mods. The problem I am having is when I get the 80 up to 55 to 60 mph when and then I come to a stop the engine dies. It does it every time I get up to at least 55 mph and as I slow the truck to come to a stop I notice the rpms drop quickly when I am almost completely stopped. The engine also tends to almost die when coming to complete stops at normal city driving.

Not to sure what to look into. Anybody heard of this and might know how to fix it? Its getting annoying when my engine keeps cutting out at stops off the freeway. Any help is much appreciated. Thanks.

Clint

VACUUM LEAK. cars starts OK right away plenty of power on take off, come to a stop car stalls again. its a vac leak , get something in a can that's flammable then with the engine running spray around all the vacuum hoses, when you hit the right spot the engine revs will go up. find the leak and fix it then your problem will go away, a vac leak will show no codes on that model car.

 

[SUMMIT CRUISERS]

Vacuum leak? Might be your brake booster leaking. As you apply your brake, booster leaks engine vacuum and stalls motor. Try to simulate a low speed version of the situation (without traffic) by using your your parking brake to slow or stop.

 

[jeffro109]

Mine did this one day, about 3 or 4 times. Exactly as described, would run fine till almost stopped then die. Happened just after the speedometer and odometer quit at highway speed.

After checking everything I could think of, drove some more on the highway, no speed or mileage signals and it would die anytime you exited. Lasted a few hours and everything came back to life, would stop normally.

Never could figure out the issue, has not come back in over a year and a half, I'll stay tuned here to see if the gurus fix the OPs and check whatever too.

 

[axolotl81]

My check engine light works fine. It lights up every time the truck stalls.

At low speed driving the engine idles fine when coming to complete stops. I was driving it around my neighborhood going from fishing lake to fishing lake with low speed driving looking for places to fish from. If I got on the accelerator a little heavier than usual before coming to a stop and pressed on the brakes then I would get the rough idle when stopped. Still a possible vacuum leak or more like the IAC, AFM, or brake booster?

If it was the brake booster wouldn't it give me a rough idle every time a pressed on the brakes?

Will dive in and troubleshoot. Gotta find some time to mess around in there and see it I can find this problem.

Thanks for all the responses. I guess I'm not the only one.

 

[jfz80]

A cracked air inlet tube from canister to throttle body can cause stalls at a light
simple thing to check to rule out.... be sure to look at bottom side of accordion section where it likes to crack from air filter changes.

 

[veeLC]

X4 IACV

Had the same problem on Elsie that went away after replacing it. Make sure it's not a vacuum leak first. IACVs cost $.. Aloha

 

[axolotl81]

Will check for vacuum leaks for sure. Its the easiest thing to do on this troubleshooting list. Thanks for the responses guys.

 

[thebus]

i vote vacuum leak as i just got it back from a local garage..(another story ), ended up like replacing everything, then bypassed or cut off one of the vacuum hoses on the intake manifold

 

[Camino]

There are a lot of vacume hoses, some ae short and just come off. L.B.

 

[chui]

hi - dont know if my issue is the same - my 80 series (1991 - manual) on long distances say constant driving at btwn 120 and 140kph, when i slow down the idling really drops low - on two occasions in the middle of the highway the car has just switched off.
when you say vacuum hoses - these would be??

 

[axolotl81]

The vacuum hoses we are referring too are the many smaller hoses coming from places all around the intake manifold, intake hose, and any other misc. sensors with vacuum hoses attached to them. There are a lot of them. Hopefully not as many as a 3VZ engine.

 

[landtank]

sounds like a sticky EGR valve. At highway speeds it's open and gets hot and then sticks open afterwards. That's the vacuum leak!

I'd almost guarantee it.

 

[jeffro109]

sounds like a sticky EGR valve. At highway speeds it's open and gets hot and then sticks open afterwards. That's the vacuum leak!

I'd almost guarantee it.

I had wondered about that. I need to finish my EGR removal...I only have the vac lines looped so it can't actuate, but planned to do block off plates.

 

[axolotl81]

Will check the EGR also. It may take a couple of days to be able to get in there because I have daddy duties. Not too sure when I will have some real free time.

 

[rhinocrunch]

Mine did this one day, about 3 or 4 times. Exactly as described, would run fine till almost stopped then die. Happened just after the speedometer and odometer quit at highway speed.

After checking everything I could think of, drove some more on the highway, no speed or mileage signals and it would die anytime you exited. Lasted a few hours and everything came back to life, would stop normally.

Never could figure out the issue, has not come back in over a year and a half, I'll stay tuned here to see if the gurus fix the OPs and check whatever too.

I know this is like 12 years after the fact but my 1992 I just imported from Japan is having the exact same problem. Did you ever figure it out? I had mine stall out and die driving down a mountain canyon and had been in a shop for the past 2 weeks but the speedometer and odometer failed right before it died as well. Freaky how similar it was to yours apparently. They took apart my dash and they think it was because of exposed copper and someone messing with it in the past. I’ll attach some pictures. If you see this, any help is appreciated.