Author Topic: 1.6TD performance loss questions (Read 3402 times)

vwnut84 · « **on:** July 03, 2008, 05:19:38 am »

Ok, so I have a 1.6TD in an '86 Jetta that is having some performance issues.

The performance problem started a few months ago when I got the car to my house, it was hard to start, and low on power. So I ended up fixing the glow plug system for the hard start and as a test I had replaced the injection pump with a known good one off of a parts car I had. The fuel system the pump came off of was closed and not open to the elements. The car it came off of was a 1.6 NA '89. I figured that the pump would be fine for the turbo as it still has the LDA on it. So I moved the boost vent and the boost enrichment fitting to their proper locations (slightly different on the non turbo car). So I installed the pump and timed it to 1.03mm and went for a test drive. It is still low on power and has a very linear and gutless powerband. I am getting 9PSI of boost, but it only hits peak boost at almost redline (about 4,300 rpm) and I am not seeing any smoke at all under a WOT 3rd gear pull.

So my next step was going to be to pull the injectors and check and make sure there is no funky crap in there and that the heat shields are not charred to nothing (seen it happen on rabbits after years of abuse)

So as far as I can tell, my timing is spot on (re checked twice) and I have no fuel leaks or boost leaks, so what should be my next diag step? I'm slightly stumped at this point.

Thanks a bunch guys. I've learned so much from this site so far and can't wait for more!

Mark(The Miser)UK · « **Reply #1 on:** July 03, 2008, 06:21:44 am »

Painful as it is drop the other pump back in and see if the power problems change. (I've assumed original pump operable)

Darkness_is_spreading · « **Reply #2 on:** July 03, 2008, 06:22:19 am »

9 PSI ? step up the boost a bit and you will notice some power but you will need to adjust the pump fuel wise to use the extra boost...

91 ECO · « **Reply #3 on:** July 03, 2008, 06:32:34 am »

Sounds like you have turned your car into an Ecodiesel. There are non-turbo pumps that have an altitude compensation device that looks a lot like a LDA but the guts are different. There are articles on the website that will detail the difference, but the short answer is that the altitude compensation does not provide extra fuel under boost.

zukgod1 · « **Reply #4 on:** July 03, 2008, 06:58:56 am »

Quote from: "91 ECO"

Sounds like you have turned your car into an Ecodiesel. There are non-turbo pumps that have an altitude compensation device that looks a lot like a LDA but the guts are different. There are articles on the website that will detail the difference, but the short answer is that the altitude compensation does not provide extra fuel under boost.

I have to respectfully disagree with this one.

I have a Alt comp pump on my TD. I took it apart to see what was in there as the pump came off a non TD engine.

Anyway, it's identical inside. The little pin that rides on the boost pin can seize up though on the Alt pumps just because it doesn't get the movement it would on a TD application.

All I did was clean it and install a nipple on the top instead of the vent and off to the races.

Also, my Alt pump had a 9mm head VS the 8mm on most TD pumps.

So adjust your waist gate for more boost, I suspect that will help.
You can also adjust the boost pin as it has an eccentric on it, turn it to deliver more fuel and you can turn the star wheel under the diaphragm to get more fuel at lower boos levels.

vwnut84 · « **Reply #5 on:** July 03, 2008, 08:04:35 am »

The boost pin in the LDA being frozen sounds very feasable seeing as it probably has not moved ever. HA So I'll take the top of the pump apart and clean it up then.

The turning of the boost screw, now is that the t25 Torx on the top or is this another adjustment inside under the top cover?

Before I turn anything up or modify I would like to get the car running perfect at stock levels (which from what I can tell is not at all) but that could just be the boost pin sticking in the LDA, so I'll start with that.

Also, when in the rev range should the boost be peaking at with stock settings? And will a lack of fuel in the lower revs cause it to not spool up as fast?

vwnut84 · « **Reply #6 on:** July 03, 2008, 08:12:14 am »

AH double post......

jimfoo · « **Reply #7 on:** July 03, 2008, 08:23:32 am »

Quote from: "vwnut84"

And will a lack of fuel in the lower revs cause it to not spool up as fast?

Yes.

jimfoo · « **Reply #8 on:** July 03, 2008, 08:32:19 am »

Don't see toe delete option for a double post. Probably double as it has been running very slow here so I didn't think it sent.

jimfoo · « **Reply #9 on:** July 03, 2008, 08:33:38 am »

Quote from: "vwnut84"

Also, when in the rev range should the boost be peaking at with stock settings?

Re-read the post. 4300 rpm to get 9psi sounds like other problems as well, stuck or mis adjusted wastegate, boost leak. As for the peak boost rpms, it depends on turbo, turbo settings fueling, timing. Basically too much for a real answer, but 9 psi should be way lower than 4300. My VNT will make over that at 1500 on a 1.9.

vwnut84 · « **Reply #10 on:** July 03, 2008, 01:05:14 pm »

Ah, then maybe I should be diagnosing the turbo instead and seeing if maybe it's past it's prime. I'll look through the bently and go over the checks for it as well.

zukgod1 · « **Reply #11 on:** July 03, 2008, 01:29:09 pm »

Whats with all the double post stuff??

Deleted my double post.

zukgod1 · « **Reply #12 on:** July 03, 2008, 01:29:09 pm »

Its really easy for the wastegate to get carbon on the sealing surface.

Last time I had mine off I lapped the sealing surfaces with valve grinding compound then screwed the torx screw on the diaphram in as much as I could

It no moving now.. Seals good as well.

vwnut84 · « **Reply #13 on:** July 03, 2008, 02:47:33 pm »

Sweet, I have a bunch of different things to try out this weekend.

thanks a bunch for all of the help! I'll post up on monday on my findings.