1994 VW Jetta III cranks and won't start

two weeks ago, on my way from from work, my jetta was losing coolant due to broken hose, got overheated and stalled right after i had parked it. now it will crank but won't start.

i first checked oil and coolant and there's no sign of blew head gasket, checked all the fuses and replaced distributor cap & rotor and spark plugs. the spark plugs wires have good continuity. i also checked the timing belt and it's is in good condition and has correct timing.

still no go

all the relays are clicking when ignition key is switched to on. the ignition coil has primary resistance of 0.6 Ohm and secondary resistance of 3400 Ohm and 12V output with the ignition key on. according to haynes manual, they are within specs.

a strong smell of gas is present in the cabin when engine is cranking, but spark plugs are dried and there's no sparks at the distributor.

and i noticed that the shift indicator in the dash board won't change accordingly to the gear shift. and the string that looks like "1n 02" is flashing in place of the odometer when the key turned to ON.

i spent the last two weekends fixing it to no avail

any idea will be greatly appreciated.

oh it's a jetta III GL model with 4 cyl 2.0L ABA FI engine

Reply to
bi241
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REPLIES WITHIN

Where was this broken hose? How could you tell there was no sign of a blown head gasket?

Possibly: Ign switch Ign coil Engine Speed Sensor Faulty main engine wiring harness plug or connections wet.

Bentley manual would be more informative. ;-) Try to start engine using a remote starter and leave the ign switched on. MAKE SURE IT IS IN PARK OR NEUTRAL!!!

Hmmm you smell gas but the plugs are not wet? That smell has to come from somewhere. Maybe you have a fuel leak......but you should still get a spark. This sounds like another problem that should be addressed.

Dash Gear Shift Indicator is not functioning??? I would examine any electrical plugs on the auto trans and engine that might have had a shower of coolant!

"1n 02" is Normal....after so many miles those service indicators will come on and need to be reset after servicing. ;-)

Reply to
dave AKA vwdoc1

hi dave,

thanks so much for the reply

the hose connecting the reservoir and the engine block was broken, a small breech near the connector, but the engine did have a good shower of coolant.. last time it stalled, it was when i tried to wash the running engine at the car wash, took about half an hour to start and run again, this time seems no hope :(

i fixed the hose, intentionally dumped more coolant and was happy to see no traces of oil, so i guess the head gasket is ok.. i filled the coolant up and wiped off the excess, and waited a few days for the engine to dry then came back and changed the plugs, dist. cap and rotor..

yeah i did remote started the car, i used a 8 gauge copper wire to jumper the starter's solenoid to battery ( + ) terminal, ignition key in ON position, gear in NEUTRAL, same thing, cranks but won't run, at least i can conclude that the ign switch is OK

i then touched the fuel injectors while cranking the engine and they are not responsive.. actually i have no idea how the injectors would "wiggle" when they are working, at the intake manifold inlet i smelled only a faint odor of gasoline

i cleaned all electrical connectors with CRC cleaner and so far evrything seems fine but no sparks, no injectors pulses

yeah haynes manual sucks.. i googled for information and narrowed the problems down to the coolant temp sensor, the camshaft sensor, the engine speed sensor and the ECU

my car has a distributor so i guess the engine speed sensor is only for RPM and the ECU wouldn't cut off ignition when it's gone bad, a bad camshaft sensor maybe the cause, but then i thought the coolant sensor got the most damages during engine overheating and i cringed when i thought that maybe the ECU is dead too..

my question is would a faulty coolant sensor cause the ECU to abandon ignition and injection? a safety measure perhaps? oh and i dont see the check engine light coming on when the ign key is ON and prior to cranking... and the OEM alarm wouldnt go off when i reconnect the ( - ) terminal... my ECU is dead?

Reply to
bi241

REPLIES WITHIN

Sounds good

They might click when working and should be working while cranking the engine over.

You cleaned ALL connections?

The camsensor (AKA ign distributor) would/should not cause this problem and the engine could run with the camsensor disconnected or bad.

The crank sensor could cause a non-start problem! I wonder if the needle of the tachometer would jump while cranking the engine?

Hmmm that check engine light NOT coming on is a clue! Start looking at the fuses and relays. But like on a '96 I had, it may just be a bulb! lol I don't think a faulty coolant sensor would cause a no-spark problem. I suppose you don't have a vag-com tool to plug into the ECM. 8^)

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Reply to
dave AKA vwdoc1

it's the ECU!!! i am sure

i dont have the vag-com.. :( it could have saved me a lot of time... but yeah i did check the fuses and relays first thing.. i just can't recall seeing the check engine light on recently, either when cranking or running, but like you said i think it could be a bad bulb, mine had been overworked. :)

i did clean all the connectors, spayed CRC cleaner on every each one them... i only disconnected and clean the inside a few connectors that i suspected getting showered by the coolant, and ones that go to camshaft sensor, crankshaft sensor and coolant sensor

i found out that in case of a faulty coolant sensor, the ECU will use the default 80 C or 176 F, so it's not the coolant sensor. also on

2.0L engine the camshaft sensor only works for advanced/retarded timing and the engine can start with it disconnected, so neither the camshaft sensor

i was able to download the bentley manual for BMW 3 series and check the Jetta crankshaft sensor following the instructions, the resistance across pin 1-2 is 570 ohms compared to 1280 ohms specs of that of the BMW. checked with napaonline and they are different part numbers, albeit looking exactly the same.. while i have no idea if 570 ohms is still within specs, at least the sensor was not completely dead, yes?

i reached under the rain gutter and tapped the ECU a few times with a wooden stick, then cranked the engine and noticed a significantly slower crank, some sort of resistance that caused by chamber combustions, though weak and uneven.... also another good thing was that the dash shift indicator worked correctly. tried cranking about five times more but still no start.

so i pulled the ECU off the compartment, unpluged the harness and examined the wires and prongs, made sure nothing was broken or loose, put everything back, and the first thing i noticed was the dash shift indicator turning wacko again.... i tapped the damn ECU again, and this time it's like beating a dead horse..

i'd probably look for another ECU at a junk yard, dont know if i'll have much luck finding used VW parts in houston TX... haha...

thanks again dave

Reply to
bi241

WELL that is one possible cause, but I say check all of the wiring from the ECM/ECU plug using the Bentley testing chart. If the ECM/ECU is not getting power and ground then it will not work. ;-) Bentley $44.07

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The ECM should be the LAST thing to suspect and change! Ign switch is one of the first I look at.

Some use the vag-com clones found on Ebay for around $20. I am not sure that they work but for $20...........why not try one! ;-)

ebay has a '95 ECM going pretty cheap right now

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You NEED to make sure all the ECM's numbers and letters are identical to yours.

Reply to
dave AKA vwdoc1

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hi dave

i'll look for it on eBay, thanks for pointing that out.. i've haven't bought anything from eBay for like two years, but i'd been an eBay junkie before...:)

long before it died my jetta would behave like a barometer, running erratically on a humid day, misfires, hesistation.. etc. now it only makes sense if a failing ECU is resposible for that.. why did VW engineers decided to hide the engine computer under the rain gutter is beyond me, did they set up their home computers in a barn too? sheesh!!!

now what is responsible for a failing computer? beside short circuit, i'd say water, heat, humidity, shock.. and so on.. and also some pointers led me to the Split Fire spark plugs that i used in the last tune up. when i pulled them out, 3 out of 4 look corroded and fouled. some people believe that the unsual shape of the electrode creates too much electro-magnetic noises (RF interferences) that eventually damaged the engine computer chip. i am not so sure about that but i'll stay with Bosch or NGK platinum from now on

til i find another brain for my jetta..

thanks

Reply to
bi241

That sounds like a coil pack.

Putting the computer in the engine compartment reduces the number of wires running thru the firewall.

Reply to
Tom's VR6

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That idea about excessive rf with Splitfire is about the stupidest thing I have heard. But I am not an electrical/electronics engineer. What kind of noise do you create with bad/leaking spark plug wires? What kind of noise do you get when a trucker drives by with a cb running at 50 watts? What do you get when you drive under power lines? What kind of RF do you get when you are around a nuclear explosion? Well I know the last situation makes for a bad day with many things electronic. But if you don't have your iodine nearby it probably doesn't matter if the heat did not get you.

The brains of most engine management computers have some basic RF shielding built in. I believe my Toyota repair manual says do not mount a CB radio next to the computer though. I am sure that also means no shortwave radio nearby.

Reply to
Jim Behning

Yeah Tom is probably right. The ign coils (ignition transformer) are a very weak link in the 2.0s and I ONLY buy new ones from the dealer. All of the aftermarket ign coils I have seen and tested have failed!!! Sometimes after a week and sometimes after a year but all have failed either providing a weak spark or no spark at all. ;-(

I have heard that using Splitfire plugs can be good if you use the proper wires to go with it for the added benefit. I WOULD NEVER USE SPLITFIRES IN MY VWS OR AUDIS. Maybe on my domestic Jeep. NOT! I prefer using the stock long life spark plugs!

Reply to
dave AKA vwdoc1

hi all,

i got into some serious seff-doubt after reading your replies, so i tried one more time before heading to ebay... or a junk yard

i gave my cheap multimeter a fresh 9 v battery, carefully selected the proper scale and again measured the crankshaft sensor resistance. it's

529 ohms and i was able to confirm the specs as 540 ohms +- 40 ohms

then i inspected the 3-pin connector that goes to the ignition module. pin 3 is a steady 12V, pin 1 is a steady ground, pin 2 is controlled by the ECU and provides disruptions to ground with an approximately 6 kilo ohms resistance when connected. i hooked up the circuit tester between pin 3 and 2 then cranked the engine, guess what?? the light bulb never flashed!!!

that's it, no spark because the primary coil's current never had the disruptions that excite the secondary coil. i can have a super duper coil and still no spark... and since the crankshaft sensor is good, the ECU must be bad...

my 1994 jetta III has a distribution system, it's not using a coil pack. by the way i think the coil pack is a very ill-concieved idea unless each coil can be inspected and replaced individually... but why coil pack??? sheesh!!! ignition by distribution has been around for as long as automobiles are...

oh i can definitly see the point of mounting the ECU in the engine compartment but i think i'd wrap my replacement ECU in saran... lol

and i started to wonder if there's a VW conspiracy... i did some google and found out that some folks were flabbergasted when they took their dead VWs to the dealers only to hear them talk in a different language, the dealer would then refer to the crankshaft sensor as impulse sender, and camshaft sensor as hall sender, and they never suggested ECU problems as if those things would never fail... such BS!!!

yeah the RF interferences theory concerning split fire plugs sounds ridiculous, but the things certainly fail to provide fuel economy as promised. i'll stay away from them.. bosch has a different approach to a multiple-electrode spark plug, but i think it just a part of automobile bull sh*t marketing...

anyway, a friend of mine told me about a yard in houston that hosts many junked VWs, i'll come by and see this afternoon

just wanted to post a follow up...

Reply to
bi241

The coil pack has the *theoretical* advantage of no moving parts. Also, one coil or drive transistor could fail and let a six cylinder engine limp home. (not sure about a 4).

The coil packs have been notorious at flash over during humid conditions, which then burned carbonized tracks into the insulator. That same sort of thing could happen with a single coil, but with a single coil there is probably more room to allow a bigger flash over path. Your description of running badly with humidity made me think of my experience with coil packs.

Let's see if that new computer fixes your car. Good luck.

If you can start then, I would still look at the engine in the dark to look for flash-overs on coil, distributor or wires. If the weather is not foggy, make your own fog with a water mist.

Reply to
Tom's VR6

thanks tom

if automobiles makers realise that they can't get away with putting lighter duty coils in a coil pack then i'd say coil pack design is superior to distributor.. i'm sure they know well about statistics as far as reliability is concerned but reducing bill of material still their number 1 priority..

anyways, i believe my ECU was shot and a new ECU will fix my car..

i went to benltley publisher's site and found this thread.. the guy's experiences with his 98 jetta is similar to mine, and dave was right, OEM ign coil works when after market units don't.. it's all about the ign module working in conjunction, i guess.. but i havent replaced mine yet..

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and then i found a used bosch ECU with matched part number on ebay for $47 shipped.. bought it and now i'm wating for it to arrive

if it can run, i'd do a water mist just to see what's going on, but i can never forget that the only times that my german lady quit on me was when she's given a steam bath.. lol

will let you guys know how it'll go...

Reply to
bi241

replying to bi241, Hulk wrote: VW should be accountable for this failed electrical system

Reply to
Hulk

replying to bi241, Enrico stoffels wrote: Hi can u hlp me my jetta 3 crank but will not start

Reply to
Enrico stoffels

So What happened? B/c I'm trying to fix my car too

Reply to
photojoe85

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