# ABA/16v swap troubleshooting (now with pictures)



## MkIII_Paul (Sep 7, 2008)

So this is the same swap project I had a while ago. The issue is that the EGT's are extremely high, and the exhaust manifold glows red under cruising conditions (around 900-1100 degrees Fahrenheit measured by a thermocouple on the manifold) I inadvertently let the thread die, but will recap here.



It's an OBDI mk3 golf with 9A rebushed pistons and a 9A head with stock cam shafts. About 9.5:1 compression ratio. I have been trying to find the root cause of the problem for a few months now, and have covered the following:

-exhaust is not restricted (one of the first things I checked). There is a large hole through the catalyst material of the catalytic converter
-intake is not restricted
-there are no vacuum leaks
-all cylinders pass a compression test
-there are no misfires
-not running lean - injectors, pump and fuel filter are new or operational (after ECU reset, I can smell it running particularly rich, but the hot EGT's persist)
-it appears to be running at stoichiometric AFR from vagcom readings
-shop that did the vagcom scan could not pinpoint any issues (though they were not experts on slightly older VW's like mine)
-timing appears to be set correctly, or at least within an acceptable range (pictures below)

A timing problem was my best guess and my main target for diagnosis, but I can't nail it.

flywheel at TDC:


distributor rotor at TDC. I am using the distributor in the block, with the same size sprockets on the cam and intermediate shafts:


cam near TDC. I don't trust the adjustable cam gear too much, which is why I checked cam position with the in-head distributor.


the spare 16v distributor. I do not run it, just temporarily installed it to eliminate any errors from the adjustable cam gear:


There's room in the slots to turn the distributor about 10 or 15 degrees, but is there a stock or neutral position? I did advance the cam timing a few degrees for a second test, with no difference.

and this is the exhaust manifold temperature (more or less steady state) at idle:


I did not drive around - just started it and let it idle for 5 minutes.

So I'm frustrated to no end, again. There's a chance that I didnt advance the cam timing enough, so I will advance it another few degrees the next time I work on it. I dont really expect any results, as I feel like I've spun the cam +/- 15 degrees in small increments, with few results. I did notice power band changes, but the exhaust temperatures have always been excessive. Any help, comments, questions, anything at all is welcome.

Thanks,

Paul


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## MkIII_Paul (Sep 7, 2008)

to the top...
confirmed this evening that it is not the chip, by swapping in a different one. 
adjusting the cam timing has gotten me practically nowhere. some temperature difference, but at idle the exhaust manifold is always above 500 F. 
I intend to try a new knock sensor tomorrow, and possibly modifying the 16v distributor with the ABA trigger wheel. I will keep in mind that they rotate in opposite directions. 

really need to wrap this project up... my daily seems to be falling apart. heater core, engine mount, control arm bushings and oxygen sensor all crapped out within a month. sigh.


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## nbvwfan (Aug 15, 2007)

You said it was stoichiometric measured by vagcom.
Did they confirm this or give you some data?
I wonder if you got a second opinion? Not trying to offend but did you check the O2 signal, or better yet get a wide-band hooked up. It might help you pinpoint the issue. If you have high EGT, it would indicate fuel or timing is off. Are the CAMs timed relative (dots pointing to eachother). (*winging this), But are you running a chip and have you check pulse duration on the injectors, or that the injectors are firing properly? I don't know how you would check this, but maybe you could throw in some green tops and see if that effects the EGT's.
At this point it does not seem like you have a timing issue, unless the ECU is pegged at an advanced condition one you have a hall pickup signal.
Just some ideas, not really definitive tips, I know, but thought I would throw some ideas out there.
I would check the O2 voltage and see if you see .56V and if it drops while you open the throttle.

Edit: 1000th post


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## MkIII_Paul (Sep 7, 2008)

thanks for the suggestions! The cam dots point to each other... theres a picture at the bottom of my previous thread (http://forums.vwvortex.com/showthre...-manifold-need-some-help-with-troubleshooting)

Yeah, I got some files and printouts from 2 different vagcom scans... lambda floats right around 1.00 at idle (doesnt drop below 0.98, and doesnt go above 1.01).

I am running a chip - a TT one that Colin programs specifically for ABA/16v swaps.

The thing that gets me is that at idle, the manifold temp is still around 580-630 F. COULD THIS BE NORMAL?????? I doubt it... anyone ever measure their manifolds after idling for a while? can some one give me a normal expected temperature?

Some updates from tonight:

I've just compared the adjustable cam gear to the stock one, and made the necessary adjustments - the adjustable one has the key placed in a slightly different spot than the stock one. Now the "stock" 16v cam gear is off of another VW head - not sure which one. are the keys and timing marks in the same spots across all 16v VW cam gears? Either way, this did not make a difference in the manifold temperature at idle. I also confirmed the ignition timing at idle with a timing light, and it looks to be roughly spot on at 6 degrees BTDC.

what really gets me is that it gets this hot at idle (though the temperature almost doubles when I'm just cruising). I'm going to have to go to a shop with this, but I'm not sure what they would do, besides retrace my steps.


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## nbvwfan (Aug 15, 2007)

If the numbers are good on the A/F side, and your timing is right, then maybe this is normal.
i did a quick google search and found similar inputs 
I see 900 at an idle. high idle about 1200.
_
wot at 1400-1600~
cruising 800~1000

1400-1450 cruising

The "unofficial" safe number is 1600. However, do NOT be alarmed if it's higher then that. Think 1700-1800. I know some people who run in the 2000 range._

I think you're ok, verify the coolant temps, and the Oil temp to give another window to rule things out. Maybe also ask the chip tuner.


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## MkIII_Paul (Sep 7, 2008)

so it seems that my timing corrections last night have brought the exhaust temps down just a hair. Driving around tonight, and I'm consistently reading 750-950 F, both at part and FOT. I might be convinced that this is almost normal, but will be taking it to the shop tomorrow anyway, as I have run out of patience. 

I've researched some EGT number too, but have found that the higher ones apply to performance/high comp/boosted engines. This one is nothing of the sort. 

Also, what concerns me is that all of the aluminum alloys I've found that might be commonly used in cylinder heads melt between 1000 and 1200 F. Now, I understand that there are coolant passages all over the head, and my coolant temp stays right in the middle of the gauge, but naturally I'm still a bit worried. Though I would be much more worried if I saw temps getting up in the 1500's.

Anyone with 16v's want to chime in with some EGT numbers? Would be great to get a nice pool of data.

Edit: Forgot to mention that I also hooked up a vacuum gauge and used the website here to learn how to read it: http://www.secondchancegarage.com/public/186.cfm

great bit of info, and a nice tool to have. My vac reading at idle is right on 15 inches, so either this is normal for 4 cylinders, or I may have my cam timing just a hair retarded still. I only caught a few glimpses of the gauge during acceleration/deceleration, but that also looked normal from what I could tell. will adjust the cam tomorrow and see if the vac reading changes at all.


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## Prof315 (Jan 5, 2009)

A glowing exhaust manifold usually means not enough timing. What are you using to control the spark timing?


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## nbvwfan (Aug 15, 2007)

Interesting 

_My vac reading at idle is right on 15 inches, so either this is normal for 4 cylinders, or I may have my cam timing just a hair retarded still. I only caught a few glimpses of the gauge during acceleration/deceleration, but that also looked normal from what I could tell. will adjust the cam tomorrow and see if the vac reading changes at all. _

I saw ~15-20 inches at idle (OEM overlap)
I now see ~25 inches after I installed a zero overlap cam (OEM G60)
Checking the cam timing would be a very good idea, as 15 inches seems like the intake or exhaust (or both) is advanced and could bias the ignition timing.
I know, I know, I have a supercharged 8v and you have a N/A 16V, but the theory relating to cam timing still might apply. I had helped another 16v 09A guy a month or so ago, and his turned out to be due to an adjustable timing gear offsetting intake and exhaust and running poorly.


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## rodperformance (Oct 9, 2010)

*timing*

16v run 10* not 6*,unless running digi1 from corrado,less initial timing will create slow burn rate and posible glowing manifold,double check spark plug burning patern,also it would be good idea to change to green tops like it was sugested a few post back,good luck i'll be watching any progress,Roderick


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## oilpangasket (Dec 5, 2007)

Prof315 said:


> A glowing exhaust manifold usually means not enough timing. What are you using to control the spark timing?



X2 Retarded ignition timing causes higher EGTs. Can even get to the point that it will make a turbine housing on a turbo glow red.


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## REPOMAN (May 3, 2001)

I argee with the previous posters. Retard timing causes high EGT. cruising at 14.7:1 A/F also can raise EGT. I set mine to 13.5:1 at cruise. it lower the temps and still maintanes desent fuel milage.
I run my 16VT setup at -16BTDC at idle. The larger bore size requires more timing at low RPM.
mine are 83.5mm not OEM 82.5mm When adjusting ignition timing the cam size/profile has a big effect on where it should be. With the vacume gauge hooked up At Idle adjust the timing until you reach the highest vacume, this is the correct timing.


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## MkIII_Paul (Sep 7, 2008)

thanks for the replies, everyone! the issue is resolved. here's a bit of info for anyone running into similar problems: 

my particular problem was that the vacuum line connected to the FPR did not actually connect to any vacuum. I used a port on the lower intake manifold which had been blocked off by the injector cups that I installed. The shop figured this out and re-routed the line. this was the single most critical problem. 

I am running the stock ABA ignition management, which I understand is very forgiving and will adjust to cover a wide range of distributor positions. Either way, the ignition timing is set correctly - no firing order problems and it looks like it advances fine through the rpm's (I will post the vacgom charts if I find some time later). The quality of the scans I had gotten from previous shops was not that great, so I didn't catch the problem earlier. 

Also, my original temperature readings from an 8v manifold were not accurate. I mounted my thermocouple to the 8v's exhaust manifold this afternoon, and got readings in the 600-850 F range. The current 16v manifold temperatures are around 700-950 F. I am pretty comfortable with these numbers, and think this is within reasonable limits. 

So in the end, my exhaust was not all that hot to begin with, and it was a fuel pressure problem that was causing it. This still leaves a question, since no vacuum to the FPR would mean that I would have high fuel pressure all the time, which would lead me to assume that I'm running rich and cooler than normal. In reality, the exhaust temperatures were elevated. Anyone want to throw around some ideas for why?


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## nbvwfan (Aug 15, 2007)

Great to hear you got to a solution. 
Now regarding your closing question. 

_So in the end, my exhaust was not all that hot to begin with, and it was a fuel pressure problem that was causing it. This still leaves a question, since no vacuum to the FPR would mean that I would have high fuel pressure all the time, which would lead me to assume that I'm running rich and cooler than normal. In reality, the exhaust temperatures were elevated. Anyone want to throw around some ideas for why?_ 

Deleting my ideas, because they may not apply or be correct. 
:wave:


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## mk2glisean (Aug 21, 2007)

MkIII_Paul said:


> thanks for the replies, everyone! the issue is resolved. here's a bit of info for anyone running into similar problems:
> 
> my particular problem was that the vacuum line connected to the FPR did not actually connect to any vacuum. I used a port on the lower intake manifold which had been blocked off by the injector cups that I installed. The shop figured this out and re-routed the line. this was the single most critical problem.
> 
> ...



the engine management will pick up the rich condition from the o2s signal and shorten the injector pulse to even out a/f


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