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Discussion Starter #1
Hey all!
Proud owner of a new to me 1998 beetle (2.0). After some minor maintenance to get her roadworthy (bushings, Passenger door latch, fluid changes,ext) a couple months back she's been running great since day 1. Yesterday when I went to leave work things started started acting up. First I went to unlock the doors with my key (previous owner didn't have the fob) only the driver door would unlocked. That striked me as odd so I tried to start the car and the alarm went off when I turned the ignition to start (no cranking). After some quick Google research I found a couple of ways to bypass the alarm. After a few trials the rear hatch trick worked to reset the alarm and allowed the car to crank over, but lead me to my current problem. The bug will crank and fire for a second or two, popping and puttering, usually revving to about 2k then dies. Also one thing I've tried and found interesting in my diagnostics was if you disconnected the battery with the ignition in the run position, even for a second, then reconnect and started the car she runs (still popping, puttering and surging) for about 10 seconds. It did this almost every time I disconnected the battery but only for one start. I've checked the battery with a load tester, air filter, ignition, can hear the fuel pump, tried unhooking the injectors thinking it may be flooding itself (hear something priming the engine and also slightly pulls the gas pedal, which ultimately ended in no fire at all) and many other diagnostics. I've come to the conclusion that the immobilizer is cutting the injectors and giving me my problems. The car is still at work an hour away so trying things is limited although I've diagnosed quite a bit so I may be able to awnser any questions you have anyway. I have tons of experience working on cars, atvs, small engines, ect so I know my way around an engine bay and am most certainly not afraid to get my hands dirty, but these alarms and immobilizers can be an electrical nightmare for those who don't do this daily, so I'm turning to y'all! Hopefully someone has been in my shoes as I need to get her running asap without spending a boatload at the stealership (this would be the first visit for me ever! If it comes to it...). Thanks a ton in advance!!
Kris.
 

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Here is a good page that walks you through the basics of troubleshooting the vw immo system:

Immobilizer FAQ and troubleshooting for VW and Audi, with key replacement tips | VW TDI forum, Audi, Porsche, and Chevy Cruze diesel forum

Here is a thread; I have been working on my immo problem and what I have learned:

http://newbeetle.org/forums/1-8-liter-turbo/61381-immobilizer-problem.html

If you are going to keep the car and do repairs yourself, I strongly recommend you buy vcds to have full control and to be able to intelligently troubleshoot and repair your VW. The tool is incredible in its abilities and can do pretty much everything a Volkswagen factory scan tool can do. cost ($250-$350 no can or can bus capable; need windows based pc to run).
The other option; cheap vw type code readers but with limited capability (cannot match, immo issues: keys, cluster, ecm, run factory diagnostic specific in depth tests etc.) Look on amazon "vag scanner" e.g. vag 405, vs450 etc.)

Ross-Tech: Home

look up vw specific trouble codes here:

ross tech wiki:

Ross-Tech Wiki



I'm on my way out the door; if you have more questions, let us know! :)
 

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Thanks for the help guys! I don't think it is the cps, I've had them go bad and it usually goes bad over time, working when it wants. Its just so ironic that the alarm went off and now she won't stay running. I know I've read the 98s don't have the immo, but it was made in October I think, maybe some 2009 ended up in it. I pulled the codes and got p01543 (tps signal to low) and p1237-p1240 (injector circuit open cylinder 1-4). I've also had a tps go bad on other vehicles and the cars will usually still run, a little rough with delayed throttle response. When I get back to the shop later today I'm going to check fuel pressure and put some gas in the intake and see what she does. Thanks again for the info! That write up on the immo system is very very detailed. One of the best write ups I've seen!
 

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The 99's don't have an immo either so its definitely not that. I would be willing to bet that your microswitch in the door is faulty, which is why you had the alarm go off. The car doesn't know the door was opened so it will rearm the alarm in 30 seconds. Then when you start the car, the alarm is triggered. This is probably all coincidental.
 

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Discussion Starter #6
Thanks Smileybug! Good to know. I thought I read some 99s had it but I may of been mistaken. Perhaps it was just bad luck. After working 6am-630pm Friday and midnight to 430pm Saturday I think I was looking for anything to blame it on! Hopefully it didnt jump timing. Any tips/tricks for checking timing or just use the light and marks like usual? Like I said I'll dive into it some more this afternoon when I make it back to the shop. Thanks again guys for your efforts! Glad there are such helpful vw owners out there.
 

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Latest update, got a little time in this afternoon. I pulled the tps plug But it made no difference other than throwing a different code. I did manage to put some gas straight in the intake and it ran for several minutes, and would of kept running had I kept dumping gas in. That writes off the timing, ignition, crank and can sensors,air, ect. She's not getting any gas... So on to the throttle body. Obviously as a new, new beetle owner I don't have the vag com tool. If I just replace the throttle body or tps by itself (if that's possible) will the ecm recognize the new part or do I need the bag com tool to readapt it anyway?
One gracious first time vw owner over here..
Kris
 

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You don't need vagcom to adapt the throttle body. Just turn the ignition key to "run" without starting the engine and wait 30 seconds. Switch off the ignition and this is it.

But I'm not sure why you suspect the throttle body at this point. Have you checked the fuel pressure? Could be the pump.
 

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Discussion Starter #9
Finally got around to messing with it again. I pulled the fuel supply to the rail and there's a nice stream that comes out when cranking the engine, and checked the pressure which was about 36psi.
 
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