# mk2 gti cranks but won't start



## 85mk2GTI (Oct 18, 2009)

I have a 1985 GTI 8v. It will crank but the car won't start. I turned it on to warm it up and it just shut off after 10 minutes, then I turned it back on and turned it off. Then I left it alone, tried it again like thirty minutes later, it wouldn't start at all. I'm thinking alternator? Anyone got any other suggestions? I haven't checked anything yet.


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## TheMajic86GTI (Aug 9, 2009)

*Re: mk2 gti cranks but won't start (85mk2GTI)*

Need more info....
How long have u owned the car?
Has the car been sitting for a long time??
Have u done any tune-ups recently?

_Quote, originally posted by *85mk2GTI* »_Then I left it alone, tried it again like thirty minutes later, it wouldn't start at all. .

What do u mean by this? Does it crank over but not start? or Does it not crank over at all?


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## 85mk2GTI (Oct 18, 2009)

*Re: mk2 gti cranks but won't start (TheMajic86GTI)*


_Quote, originally posted by *TheMajic86GTI* »_Need more info....
How long have u owned the car?
Has the car been sitting for a long time??
Have u done any tune-ups recently?
What do u mean by this? Does it crank over but not start? or Does it not crank over at all?

I just got the car on Saturday. And I'm pretty sure it has been sitting for a while because the tires are cracking. And also it's been turned on every day since Saturday. I haven't done anything under the hood yet.
It would crank over but not start, but before that, it started perfectly.


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## dirtywabbit84 (Mar 17, 2004)

*Re: mk2 gti cranks but won't start (85mk2GTI)*

Check the isv.
check your to see if you hear the fuel pump priming when you turn the ignition.
jump the fuel pump relay( piece of wire where two large spades enter)

buy yourself a bentley manual.( troubleshoot)
check your grounds
check your timing


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## 85mk2GTI (Oct 18, 2009)

Thank man, I'm gonna try all those later on today.


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## TheMajic86GTI (Aug 9, 2009)

*Re: (85mk2GTI)*

Did u empty the gas tank out and put new gas in??? Might have bad gas or water in the gas if it was sitting a long time....and adding good gas to ur bad gas doesnt help....Id do a complete tune-up if this car was sitting for more than a year..
Check both fuel pumps to see if they are working....Just for peace of mind id take the intank pump out and make sure the hose is still good being an 85 and all....
Change fuel filter,plugs,wires, cap & rotor, air filter, oil (10w40),oil filter, brake fluid and do a radiator flush and add new coolant.
Check ur brake pads, hoses for any leaks, to see if radiator fan turns on, CTS, Throttle switches, vaccum lines for leaks, injector O-rings(if hard then change) and save up for new tires if they are cracked....
I think i covered most everything....



_Modified by TheMajic86GTI at 8:05 AM 10-21-2009_


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## dkbottles (Feb 25, 2009)

*Re: (TheMajic86GTI)*

On a gas motor there are 4 things needed to run. 
1) Air 
2) Fuel 
3) Spark 
4) Compression 
1) Air is fairly simple and almost never needs to be addressed other then to make sure all the plumbing is in place, if there is a big air leak after the injection systems measures the air this can be a problem but is uncommon. Look at the air cleaner and make sure it is not plugged and all the intake piping is in place. 
2) Listen for the fuel pump, crack an injection line to see if there is fuel etc. The fuel pump relay is a common problem as noted above. No gas, water in the fuel etc are also problems. Make sure you are getting good clean gas to the injectors at about 60psi. 
3) Pull a spark plug and ground the threads, crank the motor, do you get spark? Is the plug wet with fuel? No spark will require finding the problem, coil, transistor, cables, cap? 
4) Compression - do a compression check, if the rings are bad the car will not make compression and thus not pump air, or squeeze the fuel to make it ready to go boom. 
The problem is highly unlikely to be the alternator.


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## vr2jetta (Dec 16, 2007)

*Re: (TheMajic86GTI)*


_Quote, originally posted by *TheMajic86GTI* »_Did u empty the gas tank out and put new gas in??? Might have bad gas or water in the gas if it was sitting a long time....and adding good gas to ur bad gas doesnt help....Id do a complete tune-up if this car was sitting for more than a year..
Check both fuel pumps to see if they are working....Just for peace of mind id take the intank pump out and make sure the hose is still good being an 85 and all....
Change fuel filter,plugs,wires, cap & rotor, air filter, oil (10w40),oil filter, brake fluid and do a radiator flush and add new coolant.
_Modified by TheMajic86GTI at 8:05 AM 10-21-2009_

X2
Definatly check the intake boots. They crack and the slightest intake leak can cause problems. The one on the fuel distributor you have to check carefully. They normally tear on the bottom where stress is applied when removing. Dont just yank it off, thats how they all get torn.


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## 85mk2GTI (Oct 18, 2009)

I found the problem, I'm not getting electricity when I crank it up so it won't start. Anyone know someone that's good with wiring and stuff that could help me out?


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## TheMajic86GTI (Aug 9, 2009)

*Re: (85mk2GTI)*

Check ur fuses before u start changing anything...


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## Fat Rabbit (Nov 18, 2001)

*Re: mk2 gti cranks but won't start (85mk2GTI)*

Buy a digital multimeter for around $20.00 so you can do electrical tests to see where you have power and where you don't. 
Also make sure that the battery is good and charged up. Lots of parts places will load test them for free. Parts places will also check your alternator output if you remove it and take it to them. Go to a library and get a manual so that you have some wiring diagrams for your car. If your local library doesn't have one they can likely get one on inter-library loan. FR 
Your car has a number of fusible links in addition to the fuses. But check the fuses first as suggested above. Especially check Fuse 10 which is a 20 amp fuse for the fuel pumps. Do you hear the pumps run when you turn the key to start the car? FR 


_Modified by Fat Rabbit at 6:22 PM 10-21-2009_


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## 85mk2GTI (Oct 18, 2009)

I checked all the fuses and they were all fine. Battery is also good, tried putting in the battery from my dd which is like a week old but still won't start up. I do heard the pumps so the fuel pumps are all good. There's not spark when I touch the spark plug to a metal surface so I know it's an elctrical problem. I'll try to check some different places tomorrow and see if I can find the missing/disconnected wire.
Edit: And btw, it won't start on a push start or jump start either.


_Modified by 85mk2GTI at 6:18 AM 10-22-2009_


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## Fat Rabbit (Nov 18, 2001)

*Re: (85mk2GTI)*

Either use a 12V DC Test light or a multimeter and check for 12V DC at Terminal 15 (it will be one of the two smaller terminals) at the coil when someone turns the key. If you have power there you will have to look further into the ignition system. FR


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## vr2jetta (Dec 16, 2007)

*Re: (85mk2GTI)*


_Quote, originally posted by *85mk2GTI* »_There's not spark 
Edit: And btw, it won't start on a push start or jump start either.

_Modified by 85mk2GTI at 6:18 AM 10-22-2009_

If your not getting spark why would you think it would push start or jump start? Be sure to check the ignition switch too. These go out fairly often. I dont think it would be the switch because your fuel pumps are turning on, but just another thing to check to make sure its working properly. Also pay close attention to the distributor, make sure all the wires look good. Check the ignition control module. 
If you narrowed it down to no spark, the troubleshooting process should be much easier.


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## 85mk2GTI (Oct 18, 2009)

I tried push starting and jump starting it before I took at the look at the spark plugs to check for sparks (I'm not THAT stupid) lol. I don't have a multimeter







I think I'm about to go buy one though and check for all those things?


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## vr2jetta (Dec 16, 2007)

*Re: (85mk2GTI)*


_Quote, originally posted by *85mk2GTI* »_I'm not THAT stupid

Just checking.....you never know. LOL!
If you like this car and plan on keeping it, invest in a Bentley. I know I know, "but they cost like $60". After you buy 2 parts that cost $60 and still have the same problem you will wish you had a Bentley to refer to. These books are NOT like haynes. They tell you how to test EVERY component that is testable.


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## 85mk2GTI (Oct 18, 2009)

Yeah I'm trying to buy a Bentley, I've heard nothing but good things about it. And yes I do plan on keeping the car. I've been wanting an mk2 GTI for a LONGGGGG time lol.


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## la_barbarian (Dec 23, 2016)

*My cranks-but-won't-start problem and solution*

Hopefully this will help someone out there with a mk2 that's being stubborn...

My 1991 gti (digifant) was running fine for the first year I owned it, then out of nowhere it started randomly not starting. It cranked perfectly fine, so I knew it wasn't a battery issue. Recently this started happening more often than not, until last week when it refused to start completely (I used to just make sure all the fuses and relays were in and then it would start, but this time no such luck). After checking the starter, fuel pump, ignition, and the wiring to each of those, I FINALLY found the problem: a bad relay. The digifant control unit relay had passed the clicking test, so I dismissed it the first time I checked all the relays, but after checking everything else I decided to check them again. It turns out the contacts inside that relay were bad, and I wasn't getting continuity when the switch was closed. I cleaned the contacts, got continuity, and put it back in, and now it starts every time (knock on wood). I picked up a spare relay just in case this ever happens again.

MORAL OF THE STORY: check your relays for continuity, because even if they're clicking, they're not necessarily doing their job!

This whole ordeal caused me days of frustration, so hopefully my story can save someone some time and headache


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## Butcher (Jan 31, 2001)

A common Vortex issue is 'real' diagnosis is replaced with a pseudo tests and replacing parts. 

A 'click test' is not a test at all. Proper tests are done with tools and common sense. Relays go bad all the time. I just recently diagnosed a Mercedes S Class, intermittent no start, 3 shops could not resolve it. It only took 5 mins to locate the issue. Yup, the common 4 post fuel pump relay with burnt points. Diagnosis was testing the fuel pressure [and found none], testing the power supply to the pump [found 0v], and checked the power supply to the relay [12v]. Simple to bust open the relay and check the points, yup, burnt. Cleaned the points, it ran. Started several times throughout the day. Ordered and replaced the relay. The owner is happy with a $50 repair bill. Not so happy with loosing $500 on the other shops parts replacements.

Glad you resolved your problem before Christmas.


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## Jettaboy1884 (Jan 20, 2004)

Find the plug that is on the side of the spark distributor. Check the plug itself, but also work your way up the wires and look for any breaks. Those wires (the hall sender) seem to get heat soaked and brittle over time. 

When I did the clutch job on my old Mk2 I didn't unplug that hall sender connector, and the movement of the engine up and down as I was pulling/replacing the transaxle was enough to tug on the brittle wires and cause a break. The motor would crank & crank and get fuel, but no spark.

Be careful you don't hydro lock the motor if you've been cranking it for a while without ignition while it's dumping fuel. If you have, maybe worth pulling the plugs to dry them out, and also turn over the motor (which will spray the gas out of the plug holes).


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