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First time removing IP, some questions
by
dangerous_D
on 30 Nov, 2009 22:18
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First of all, a big shout out to this forum for being the best forum I've ever been a part of. Without this forum I would not have had the confidence to undertake this job. Thank you, forum members, especially the power users. Now onto the good stuff...
The car is a 1981 Jetta Special Edition 1.6 NA with AC. The IP started gushing fuel so I finally decided to pull everything apart to reseal the IP and replace the water pump. I've already taken everything apart, installed the new water pump, cleaned and replaced the accessories and brackets, and replaced the seals on the IP. The injection pump is still off the car. Before I took everything apart I checked the timing. Three times. I got 0.048", 0.049", 0.048". This comes out to 1.22mm. Based on what I've learned in the forum 1.22mm is excessively advanced and should result in poor performance and poor mileage.
The car was running really well despite the leaky IP. I bought it in April with 148k miles and I've put 7000 miles on it since then. I was getting 42 mpgs, but when I replaced the injectors it went up to 46 mpgs. The only time I saw smoke was a VERY light haze on cold start that I usually didn't notice. There was a too-rough idle on cold start, which appeared only after replacing the injectors. The manual cold advance lever had no noticeable effect on idle.
Before I reinstall the IP I wanted to get some opinions from the forum members. The specs on Vince's page lists 1.15mm +/- 5mm for the 1.5 NA injection pump. I wonder if I have the 1.5 NA pump. How can I tell which pump I have? If not, did I do something wrong when measuring the IP timing, or is 1.22mm realistic? I was also surprised to discover my crank gear bolt is a 17mm 6-point. Any idea why I don't have the 12-point 19mm bolt?
Thanks for reading!
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#1
by
dangerous_D
on 30 Nov, 2009 23:30
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I've done some more (re)reading tonight. The injectors that I replaced popped at 118 bar and the replacement injectors popped at 130 bar. These numbers are from Giles, so I believe them to be accurate.
Now I am confused even more. At 118 bar would the car even run at 1.22mm (let alone run well)? I suspect the pump pressure is off.
Thoughts?
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#2
by
burn_your_money
on 01 Dec, 2009 06:30
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Early engines used the 6pt bolt on the crank instead of the 12pt. The 6pt is now obsolete and the dealer only sells the 12pt. I don't see any need for concern because of this.
When you checked the timing did you use the flywheel as your TDC reference or your cam? It should be the same but often it isn't. Did you rotate the engine in the direction of rotation (clockwise)?
As for retiming the pump I would go ahead and install it at 0.95mm and give it more or less advance depending on how it is running.
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#3
by
rabbitman
on 01 Dec, 2009 09:55
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Was the cold start lever on the pump in the "pulled" position when you checked the timing?
X2
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#4
by
dangerous_D
on 01 Dec, 2009 09:59
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Thanks for your replies. I will use 0.95mm as my starting point when re-timing the pump.
I used the flywheel to check the timing and followed Vince's procedure (find TDC, rotate backwards until gauge stops, zero gauge, rotate forward back to TDC). I did this 3 times and each time I changed the pre-load on the plunger.
The cold start lever was in the "off" position. The cold start was the source of the large fuel leak and the position of the lever never had an effect on the idle characteristics of the engine (at least not an effect significant enough to notice).
I've read other posts on this forum about pumps needing extreme advance (according to the gauge) in order to work properly. Most of these threads concluded that tired, old pumps might need more static advance. I wonder if this can be corrected by adjusting the internal pump pressure.
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#5
by
smutts
on 02 Dec, 2009 09:21
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I wonder if this can be corrected by adjusting the internal pump pressure.
It certainly can, my best guesses for the 1.6 TD's are as follows...
36-46psi@1000rpm, 67-75psi@3000rpm, 94-103psi@4500rpm, these are engine rpm's. Google "hagar" and "smileage" for how to check the pressures.
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#6
by
dangerous_D
on 02 Dec, 2009 09:30
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Google "hagar" and "smileage" for how to check the pressures.
Lol, I've read his entire saga. Thanks for the numbers.
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#7
by
smutts
on 02 Dec, 2009 09:40
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His figures though might be a little bit fierce, but good luck.
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#8
by
dangerous_D
on 18 Dec, 2009 16:02
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Turns out I was checking the timing 180-deg out.
I made haste and got sloppy. Lucky for me I was smart enough to mark everything before disassembly so I lined up the cam and crank to the marks on the original timing belt and slowly turned the crank a complete revolution to clyinder 1 TDC (from clyinder 4 TDC).
Bummer that I don't have any valid "before" timing measurements. I'll post again when I have her running and tuned.
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#9
by
burn_your_money
on 18 Dec, 2009 16:23
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Pump timing is the same whether you are 90, 180 or 270 out. As long as you are at TDC for a specific cylinder it's all good.
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#10
by
dangerous_D
on 18 Dec, 2009 17:15
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That is very useful information. Thanks!
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#11
by
dangerous_D
on 22 Dec, 2009 20:40
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I put everything back together and timed the pump to 0.039". She REALLY wanted to start, and with the starter engaged and the "pedal to the metal" she was very close. When I released the starter the engine passed away. I'll move up to 0.044 and try again. Probably not until after the new year, though.
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#12
by
dangerous_D
on 23 Dec, 2009 07:27
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I REALLY wanted to get her started before I left for vacation today and I decided to try one more time without adjusting the timing. This time I pulled the cold advance knob and after just a few seconds of cranking she turned over! This suggests to me that 0.039 is still a bit retarded for my pump. I'll have to tinker when I return from vacation. It's a very satisfying feeling to have done all those hours of work and achieve success in the end. I'm not surprised, though. I wake up in the morning and I piss excellence.
I will post final timing numbers when I get there. Internal pump pressure adjustments are probably not realistic in the near future.
Happy HolidayS!
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#13
by
dangerous_D
on 17 Jan, 2010 23:05
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Everything's running great, but I'm a bit confused. The weird thing is I didn't touch the IP timing. Three weeks ago I couldn't get the engine to turn over at this IP setting. I checked the timing with the cold start knob engaged and the timing was actually more retarded than when the cold start "advance" was off. I turned off the cold start advance and measured the timing at 0.040". She starts and runs beautifully! I assume I reinstalled the cold start mechanism incorrectly when I replaced the seals on the IP. The only thing that is different between the no-start condition and the start condition is that the cold start lever was cycled.
Aside from the "cold advance retard lever" he only out-of-the-ordinary thing I noticed is a splattering of oil from the tailpipe. It only happened once when starting her up after sitting for nearly 7 weeks. I'm not too worried since it doesn't recur.
Anyway, I just wanted to close out this thread. If my mileage is significantly different than before I performed all this work I will repost.