2.1 dies after 40 minutes in extreme heat-SOLVED

[davevickery]

Can anyone help? My van runs fine for 30 minutes or so then looses all power and if I pull over, it will idle for a minute before dying. Running it on the highway or around town doesn't matter. Won't restart right away but waiting a few minutes it will start right up and run for a few minutes before dying again. Waiting a half hour, it will run for 15 minutes. Overnight it will run well for 30-40 minutes again. It is obviously fully warmed up long before it starts to stall out. It has suddenly gotten much worse. Does anyone recognize these symptoms.

Could AFM produce these symptoms, how about 02 ground. Many routine parts have been replaced. Hall sender connector is a little loose and I have it zipped tied.

I searched and found someone else posting this description of the same issue, but no replies to his post.

This has been a repetitive problem and has gotten worse recently. Our 1990 Vanagon loses power and stalls in hot weather after being driven for some miles. It will begin to hesitate (feels like it is cutting out) and this symptom increases until it is bucking and has to be pulled out of the traffic flow. Once stopped and turned off, the engine apparently cools off enough to proceed for a further distance and then the stalling and bucking begins again. When we got it used about 8 years ago, we would only experience this in the hot desert weather (central Washington state - Summer - 80F - 90F degrees - highway & slower). Now it happens in cooler weather and is almost undriveable. It has been to 3 different Vanagon repair and maintenance shops - a tune-up is always done and it still performs this way. Generally the staff do not have time to road test the vehicle to the point of failure so it is just our word against the van's around the block performance. The failure is so predictable that we could bet and win money if there were takers.

My guess as an armchair mechanic is that the engine temperature is causing a disruption in the fuel injection and that there is one part that is responsible. Any ideas?

Thanks - Mike

[ShultzRoadHouse]

Have you checked your timing? Any vacuum leaks?
_________________
ShultzRoadHouse
'81 AirCooled Westy RIP
'82 Westy w/ '93 Subaru EJ22
'71 Super Beetle w/ '75 AJ 1600
'12 Jetta

[nomados]

Mine does something similar to this, though it's not at your stage yet. When hot, climbing a hill, turning to the right it dies right out (big buck) but comes back again. The hotter it is the more extreme the "cutout". I agree with you, that it is most likely a sender or FI related problem. To me it seems as though the fuel is cut right off but then comes back.
I'm in the same desert BTW, just north. Mine only does this when on the hot side. The right turn/ up hill/ hot combination had me very curious, hopefully it may help you to narrow down this gremlin; I'll be watching to see what you find.
_________________
'86 Westy auto
'84 Westy 4 spd previous
'75 wing, watercooled boxer 4 motorcycle.

[heidi85ho]

CAT?

[0to60in6min]

this symptom is very similar to vapor lock on engine with carb... I am still searching a solution...

[davevickery]

[0to60in6min]

there is a sensor that regulate the amount of the fuel/air mixture according to the coolant temp... it's Temp2 sensor

how old is yours? it's cheap to replace for insurance..

[alnvilma]

I have posted to other inquiries about warm engine failures and here's my $0.02:
I had what I thought was fuel starvation after warm-up and it turned out to be a bad coil AND, the coil was new! It was shorting out when it warmed up but would restart after cooling. It's easy to check if you can borrow someone's and test drive it.

[davevickery]

[davevickery]

I think I have this narrowed down. Maybe either fuel pressure regulator or fuel pump as the mechanic suggested. It would never restart immediately after quitting. When I unscrewed some of the fuel lines and relieved pressure or just got air out (not sure which), it would restart immediately. I'm not sure how much is supposed to gush out when you pull those hoses off right after it has been running; nothing out of the return line, and a lot of pressure out of the other two. And possibly some air from unscrewing the little port they use to testing the fuel pressure regulator. Anyway messing around with those after it quits, it starts right back up (and quits again a bit later). I have a spare regulator, so I am going to try that first.

[davevickery]

It isn't the fuel pressure regulator. I tried a spare and it did the same thing. I read about similar intermitent hot dying symptoms from the fuel pump or the fuel pump relay. The failing pump runs hot and shuts down, and the relay has loose contacts that don't make a connection once they heat up. I think these can be tested pretty easily, but I am not good at that. $10 for a relay sounds like the next step, then $110 for a fuel pump if the relay doesn't do it. I hope I'm getting close.

It is curious why releasing some of the pressure in the fuel line allows the van to restart immediately. It doesn't stay running for too long, but helps getting the van home from test drives. I'm keeping in the back of my mind that the mechanic said it sounds like it is vapor locking from a failing fuel pump. But I'll try the relay first.

[alnvilma]

Do you have an aftermarket gas cap? Maybe the tank needs a venting cap?

[insyncro]

Check the return line at the tank.
I have seen the plastic line coming from the engine crush when hose clamps are too tight, restricting flow back to the tank and making the engine run rich and stall.

[heidi85ho]

davevickery

my experience with a clogged CAT on two vehicles, my 85 4-runner and my 85 westy, has been similar to the conditions you describe. Both ran fine until hot, then loss of power and finally shuts down. When cool, starts right back up and runs good until hot. Worth checking.

Tim

[86Carat]

Had a very similar prob a few years back... ran fine until up to temp, then missing and spluttering, finally stops and will not restart until cool, half hour or more. in my case it was the hall sender/baseplate in the distributor which was acting up when it got hot, but i changed many parts unnecessarily before i found out thats what it was, just an idea, may be totally wrong!

[davevickery]

Thanks for the new suggestions.

I could see a blocked return line causing vapor lock kind of symptoms, but the prospect of pulling the tank just to find nothing wrong is discouraging.

I thought the hall sender/distributor might be a possibility too. I missed an epay auction on a nice clean one a couple days ago. I am waiting on a new fuel pump from busdepot now.

I'm surprised the cat would cause these symptoms. I will keep it in mind though. The one thing I found that I think is telling, is releasing pressure on the fuel lines by opening up the test port allows the engine to restart immediately, when otherwise it would take 15 minutes or more or cooling down. That makes me think bad fuel pump, or return plugged. I notice the fuel pump was louder than normal after it had been running a while yesterday.

I hope I get an answer when I replace the fuel pump, but I'll look at the return lines, cat and distributor if not. Thanks

[keithwwalker]

Running hot is a symptom of running lean. I had a similar issue where my doka after highway driving would pull into a drive through and then stall.

Couldn't figure it out, then I pulled off the big rubber boot that is in between the central intake plenum and the AFM. It was cracked!

It let the engine run lean and hot and on hot summer days, it was too much.

Also replace the basics like the vacuum lines, the air intake hoses leading to each cylinder and the fuel filter(s). Combined you can get new parts for under $30 or so, and you don't have to worry about them for a long time.

[Ahwahnee]

My guess is a bad coil (Bad Coil! Bad!).

When my coil was failing it would only show up when things got really hot (like a long drive up a mountain) then the engine would begin to cut out. Doing anything with the engine cover off (like you messin' with the fuel) would enable the coil to quickly cool down enough that the problem went away for awhile.

Could also be the Temp2 sensor as the typical failure mode is that the 'puter thinks the engine is cold even after it has warmed up -- but I don't think it would take as much time as you describe for that to show up.

These are parts that (my opinion) we should all be carrying known-good spares for -- a used coil is about 5 bucks and new T2s are cheap too. Tests are possible but for these things I just swap in my spare and see if that did it.

[davevickery]

The engine isn't running hot. The extreme heat is outside temps in the 90s. It stumbles for a split second occasionally when the temps are in the 70s or 80s but it completely dies in the 90s after running for 40 minutes. Coolant temp is right in the middle of the gauge.

[crazyvwvanman]

Instead of buying more parts to try, why not do a few more simple tests? That way you will learn somethings and even if in the end it doesn't help you this time it will give you a better base of understanding for future problems. It may even point you in the true direction for the current problem before you spend money on parts that don't help or that make things worse.

Test the fuel pressure, while working fine and while it won't start after it dies. Test the fuel system delivery quantity, by the book, off the return line. Test while working fine and again after it dies and won't start.

Do the fuel pressure test first but also do it while doing the fuel quantity test. It is critical for the pressure to be within reason during the quantity test.

Mark