throttle dies, comes back, no CEL

Lurchalicious

Veteran Member
Joined
Mar 10, 2008
Location
KY
TDI
02 Jetta TDI
***CASE CLOSED***

After picking the wiring harness apart for the additional relay that was added to switch the lift pump on, a short in a small negative wire was found - this caused the pump to shut off; then combined that when this particular lift pump is shut off it only draws a small amount of fuel through a valve in the middle of the pump - as soon as that valve is no longer covered there is no fuel at all which was the cause of the "no fuel" when the tank was half full.

***UPDATE 9/22***

OK, here we go with this... I replaced the 109 relay today when I got home from work and saw the Idparts box on the porch - thanks for the quick ship pete! - starting the car this time was different.

Make note the car is little below half a tank (385 miles out of 520) keep this in mind because I want to know if I am on the right track here;

Took two seconds to start the car - almost like there was no fuel; then the car fired up. I shut it down and waited a second, turned the key again and it fired up instantly.

Popped the hood to check the fuel lines to the IP - looked fine and I didnt see any air.

I am was then driving down the road and then felt the engine cut out (I'll reference post 4 of this thread http://forums.tdiclub.com/showthread.php?t=236991). I came to a stop. Previously I was able to continue on after it caught back up and the engine started again. Not the case as it just sat dead and turned over but never started, as if it had no fuel.

At a drive thru it died at idle - this time it would not start at all and I had to push myself to the nearest parking spot. There was nothing but dribble amounts of fuel in the lines at the IP.

So I am inspecting the lift pump and its connections. I have now noticed it is not kicking on when the key is at the on position as it normally should. (It has also gotten rather loud; if the pump is failing would that explain bad fuel pickup at half a tank? the pickup should still be submerged so I am not sure on that being it but I know i should not be able to hear it outside the car when it does run. )

I sat in that lot for a while with the key out of the ignition, and decided to start turning the car on and off to some cycles of the power system and hopefully kick the relay over as I did not have a test lead to give it power and force the lift pump on. FINALLY i got the lift pump to turn on and saw some fuel starting to flow back into my lines at the IP. the car started and idled well so I closed the hood and boogied over to the next door BP station to put fuel in the tank ( I was little past 1/2 full). I added 8 gallons and left the car on with the engine off while I fueled. I could watch fuel fill up my IP lines as it was being dumped into the tank by the station pump and fed by my lift pump. alright! we have fuel and the air is gone! Started the car and took off for home, did not notice a hiccup or problem on the 2-3 mile ride home.

now we are narrowing down the initial problem - now ruling out the 109 relay - this seems fuel/lift pump related. Also a correlation between how full the tank is and the frequency of the problem has been found.

here is what I did tonight

The lift pump was purchased in april and I contacted the supplier for a claim on the 1 year warranty

tested the fuel filter by using a mighty vac and fuel came out immediately. Also drew vacuum on the return line to try and eliminate any air that may have been in the line.

signal wire inspected and found no chaffing or bad spots, wire showed fractional ohm load and had continuity with a tester

I used a wire lead to give power to the fuel solenoid on the IP where the signal wire attaches, and the relay functioned.

after verifying the relay function I checked power at the lift pump, 12v was found at the pump.

I sucessfully replicated the problem of the pump not kicking on, with the car on and the lift pump not operating, I checked power at the connector of the pump and got nothing. With that, I used the wire lead to kick the relay on. I then got 12v at the pump

Lift pump relay was responding when tested with 12v. I could not find out why it was "sticking" or not responding to the signal wire intermittently. Using the test lead attached to the battery and the fuel solenoid on the IP, I drove to the Oriley up the street to get a new relay. The problem of shutting down did not occur on the way there. When I pulled into the store I shut the car off and tried to feel the pump; it was not working. The lift pump was not working while a 12v lead was attached to the IP and the relay signal wire. I have replaced the relay with a standard 4 pin 30a 12v relay from LAPS (doorman brand).

I am driving to work tomorrow, hopefully I am not stranded on the road and the car operates normally - I do have a full tank as well so perhaps I will not see problems back until I start to get lower in fuel level.

*** UPDATE 9/20 ***

The frequency of cut out is increasing - 109 relays are on there way.

A question i have; when the engine restarts itself while driving white smoke comes out - this worries me. Should I be?
Also have noticed some of the occurances are not just engine shut off; and that is slowly dies to 0 rpm. I can try to use throttle and will notice boost will only go up to a certian point say 20psi, but then die back down.

I remember there being a post about resetting the fuel cut off valve oring in the IP - but I cannot find it to compare if I have a problem with that part. does this ring a bell?

***UPDATE***

While driving home from work I experienced the cut out again, crusing around 80mph. This time I took the car out of gear and put the transmission in neutral. The engine was dead - no RPMs, radio was still on, fans blowing, steering wheel started getting stiff (my guess is because the power steering pump was slowing down due to the engine not running) that was the cause of the battery light. This is now a issue of the motor dying at high speeds. I have yet to experience this during "in town" stop and go traffic.

Putting the car back in gear and power came back almost right after that.

Ground wires?
IP solenoid?
Fuel cutoff valve?

If a mod could modify the title to read "engine dies at highway speed, restarts itself. no CEL" i would appreciate it

***UPDATE***

Original post:

Looking for some help in diagnosing a problem I am having, its starting to make me worry. this started within the last week.

Issue: crusing at highway speeds in 5th gear a feeling of the engine braking itself will happen and there is no throttle response - the car will remain at idle speed. When attempting to give throttle there will be a haze of white smoke coming from the exhaust, after a second or two -everything will be fine and full boost is back, throttle is back. No check engine light has come on yet.

Today I experimented with the "dead zone" and took the car out of gear while going about 80 and no pedal response; the battery light came on, there was still no throttle response, engine is dead. Put the car back in 5th and shortly after the throttle came back to full and was fine.

Background of the vehicle:
02 jetta GLS manual 156k miles
2k miles with colt stage II cam (oil changed at that time)
approx 7k miles with setup in signature before cam job (28psi tune w/MAF delete, 1756vk, lift pump, 11mm, SMIC, R520's, breathing mods) - 9k total with heavy mods.
Running Power service in each fill up (grey bottle)
have been getting 38 mpg with spirited driving, 40 if I baby it

What I checked/have done so far:

Glow plug light comes on when starting the car
Car starts very easy, very quickly
fuel filter was changed in the last few months (6/14/12 to be exact - used a WIX filter from LAPS)
Oil level is good
in VCDS, at idle, throttle sensor responds 0-100%. Timing is dead on.
Idle is smooth and steady
hose clamps are all tight
no excessive oil in intake
I have the newest 109 relay - grey
vacuum pump pulls 30hg
actuator line holds vacuum

What I am looking into/suspecting:

I am calling VW to make sure my VIN has had the brake light switch replaced.



Throttle sensor intermittent failure, just not full failure yet?
I want to check to see if the pump is delivering the amount of fuel requested at time of the problem but its hard to guess when that happens, what group(s) should I watch for? (this way maybe I can log my trips to and from work and hope i catch it in the act)

thoughts? Ideas?
 
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RT1

Veteran Member
Joined
Apr 14, 2006
Location
Central New Jersey
TDI
2005 Golf 1.9 TDI w/tiptronic 09A
Relay 109 often brought up as the culprit for sudden cut-off of the engine, recheck (even if it is gray)
 

Lurchalicious

Veteran Member
Joined
Mar 10, 2008
Location
KY
TDI
02 Jetta TDI
Order 2 that way you will have a spare, shipping cost is the same.
I actually did because of the wife's golf :D, i just hope this is the whole problem. electrical problems in cars are not enjoyable to me ( i dont know of a person sadistic enough to like them)
 
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Lurchalicious

Veteran Member
Joined
Mar 10, 2008
Location
KY
TDI
02 Jetta TDI
new question in original post

The frequency of cut out is increasing - 109 relays are on there way.

A question i have; when the engine restarts itself while driving white smoke comes out - this worries me. Should I be?
Also have noticed some of the occurances are not just engine shut off; and that is slowly dies to 0 rpm. I can try to use throttle and will notice boost will only go up to a certian point say 20psi, but then die back down.

I remember there being a post about resetting the fuel cut off valve oring in the IP - but I cannot find it to compare if I have a problem with that part. does this ring a bell?
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Seems to me that even if you added a lift pump the ALH doesn't need it so it should still run if the pump quits.

Unless it blocks flow when stopped. I don't think so or you wouldn't have been able to pull fuel with a vacuum pump.

Maybe you have a leak in the pick up tube in the tank and the flaky pump/relay are coincidental. Could it have been dead a while and you only noticed it now?

The o-ring is not your problem. It is physically impossible for it to move out of position like in the pics you see while running.
 
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Lurchalicious

Veteran Member
Joined
Mar 10, 2008
Location
KY
TDI
02 Jetta TDI
Seems to me that even if you added a lift pump the ALH doesn't need it so it should still run if the pump quits.

Unless it blocks flow when stopped. I don't think so or you wouldn't have been able to pull fuel with a vacuum pump.

Maybe you have a leak in the pick up tube in the tank and the flaky pump/relay are coincidental. Could it have been dead a while and you only noticed it now?

The o-ring is not your problem. It is physically impossible for it to move out of position like in the pics you see while running.
agreed, I think it is a coincidental problem

I am thinking there is a problem with the pickup tube as well - since the problem seems to be gone with there being more fuel in the tank; and it got worse when more fuel was used.

I am going to get a warranty claim hopefully with the supplier
 

notsofast

Veteran Member
Joined
Sep 5, 2007
Location
Moseley VA
TDI
2003 Jetta
Similar symptoms, but not quite

Don't want to start a new thread and this seems closest. My A4 will sometimes act as if the fuel supply is abrubtly cut. Here are some specifics.
*Most likely to happen in first minute OR after >10 minutes of running steady.
*Does not seem to happen on cruise control.
*If I back off throttle and then reapply it either fixes it completely or sometimes I have to do that 2-3 times in a row before all good.
*Before and after fuel filter change
*Full tank, half tank or near empty doesn't seem to matter (except one time it was worse than normal when i was nearly empty. Other times near empty and it doesn't happen)
*I have VAG-com and drove to work while logging measuring blocks 2 and 8. When it happened throttle was ~30% but torque request (mg/str) was 0.0 All other times throttle percent is about 2x torque request
I'm not noticing other problems.

Relay 109?
 

Lurchalicious

Veteran Member
Joined
Mar 10, 2008
Location
KY
TDI
02 Jetta TDI
Don't want to start a new thread and this seems closest. My A4 will sometimes act as if the fuel supply is abrubtly cut. Here are some specifics.
*Most likely to happen in first minute OR after >10 minutes of running steady.
*Does not seem to happen on cruise control.
*If I back off throttle and then reapply it either fixes it completely or sometimes I have to do that 2-3 times in a row before all good.
*Before and after fuel filter change
*Full tank, half tank or near empty doesn't seem to matter (except one time it was worse than normal when i was nearly empty. Other times near empty and it doesn't happen)
*I have VAG-com and drove to work while logging measuring blocks 2 and 8. When it happened throttle was ~30% but torque request (mg/str) was 0.0 All other times throttle percent is about 2x torque request
I'm not noticing other problems.

Relay 109?

with mine I had no engine light - i am guessing you don't have a code either. relay 109 is the first place to start. I would post your log along with your modifications to a new thread; if your throttle is %30 and mg/str is 0.0 that sounds like a problem involving the IP
 

notsofast

Veteran Member
Joined
Sep 5, 2007
Location
Moseley VA
TDI
2003 Jetta
I've gone 7 days without any issue since replacing Relay 109. If it comes back i'll start a new thread with prior details and anything else that happens. (and yes, no code, just a momentary and frightening loss of fuel)
 
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