Author Topic: Sputtering diesel? Dr. Diesel help?? ;). (Read 8332 times)

VW Scully · « **on:** December 28, 2006, 03:22:29 pm »

Hey guys;
I got a line on a '91 Jetta coupe NA Diesel and it's in great shape except it runs as if there is air in the system somewhere. :? According to the current owner, it runs great when it's wide open; i.e. on the freeway or high speeds, but it sputters and doesn't want to idle and feels like it's gonna stall out when it's going slow or stopped.

I think I am going to buy the car anyway, cuz all the parts will be interchangable with my Rabbit (among other reasons
:wink: ), but I want to address this issue ASAP.
Any ideas??
Thanks!

andy2 · « **Reply #1 on:** December 28, 2006, 03:36:09 pm »

When was the fuel filter last replaced?In most cases either the fuel filter or its o-ring is the problem.

VW Scully · « **Reply #2 on:** December 28, 2006, 04:43:33 pm »

Well, the fuel filter is brand new. I'm just wondering if the current owner didn't prime the system right when he installed it. However, right now the filter is bypassed in order to diagnose the problem, but he hasn't really gotten anywhere with that :? . The thing is, even if the filter is bypassed, if air got into the system while it was being changed, bypassing it is NOT going to remove air from the system.

Would you know of any other causes though??
Thanks!

wolfsburgnut · « **Reply #3 on:** December 28, 2006, 04:50:13 pm »

Can you see air bubbles in the supply line to the pump? I had the same problem as you, air getting in the system, and I just went and replaced the flexible line from the pickup at the tank to the solid line because the clamps were rusted off and the line was cracked. After that I replaced every single clamp in the fuel system with the rolled fuel injection type clamp. Now I hardly ever see air in the fuel lines.

Peter

745 turbogreasel · « **Reply #4 on:** December 28, 2006, 05:06:37 pm »

If you don't see air in the inlet line, a lift pump may help for awhile.
tighten every hose clamp a hair, and see if that helps.
look for cracked hoses.
bad idle could be a weak headgasket too.

Darkness_is_spreading · « **Reply #5 on:** December 28, 2006, 06:25:44 pm »

If you have the bypass on now and your still getting air in the inlet line, then theres a problem farther back, it might be the fuel water seperator.
If not reconnect the filter in the engine bay, refill filter and connect back to IP.....

Then beat the living crap out of it, the air will purge out and you should get you idle back to normal. I did this jsut today for a friends Jetta, damn air, but a few burnouts and some power shifting and the air said good bye.

Check the flexible return lines of the Injectors they may crack and let air in or fuel out...... Also check the injectors may need a purge with some ATF.....

rabbitman · « **Reply #6 on:** December 28, 2006, 11:38:06 pm »

I think your timing is retarded, mine did the same thing untill I advanced it. Try pulling the coldstart knob while it idles and see if it cleans up. If it idles better than thats definitely the problem 'cause the coldstart advances it at low rpm. Hope this helps

Patrick · « **Reply #7 on:** December 29, 2006, 04:55:20 am »

Use that thing for a daily driver in the winter and do a turbo engine for the bunny!

Could use a GOOD mark 2 diesel car here, the '92 with 580,000 is getting to the point where I'm fixing constantly...... engine is a lower mileage vw factory rebuild, LOTS of new parts on the car..........

Don't want to switch out a gasser for a diesel, lots of gas cars around, but lots of extra work.

burn_your_money · « **Reply #8 on:** December 30, 2006, 06:52:42 am »

Is this Samuels car? If it is I just did the t-belt on it. I know a bit about that car so if it is PM me and I'll fill you in.

VW Scully · « **Reply #9 on:** January 02, 2007, 08:55:15 pm »

Burn-your-money; the car is black and is in Stratford at a friend's shop. Know who it is??

Anyway, hopefully I'm going to look at it again this weekend and try to figure some stuff out!

burn_your_money · « **Reply #10 on:** January 03, 2007, 04:31:38 am »

No sorry, I'm thinking of a different car

VW Scully · « **Reply #11 on:** January 03, 2007, 08:18:31 pm »

bym;haha oh well, too bad, cuz it would be nice to know if the timing belt was just done on this car!

However, it might need a headgasket anyway, so maybe a wrenching GTG would be in order when I get it :wink:
I'll keep you all posted!

vwnut20 · « **Reply #12 on:** January 03, 2007, 09:47:32 pm »

Eh Scully, Dr. Diesel is sort of out of the country right know. And I don't know if He'll be on the net anytime soon. Are you in a mad rush to get this car going? And bye the way, is there alot of black smoke shooting out of the exhaust on Idle. Are you having a hard time starting (cold or warm). Does is smooth out when cold start cable is out. Sounds alot like the pump needs be advance slighty.

Let me know, your little problem sounds interesting.

burn_your_money · « **Reply #13 on:** January 04, 2007, 04:27:27 am »

Quote from: "vwnut20"

Sounds alot like the pump needs be advance slighty.

That's what I was thinking. Especially if it was the car I was thinking about. I didn't have any special tools when I did the belt so I guessed for everything. It ran pretty good, definitely better then it did before the new belt, I'll take some pictures to emphasize my point lol

rabbit_diesel · « **Reply #14 on:** April 27, 2007, 09:03:27 pm »

Same as my Jetta, I just turned on the pump a bit. :wink:

Author Topic: Sputtering diesel? Dr. Diesel help?? ;). (Read 8332 times)

andy2

745 turbogreasel

vwnut20