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andyrew
02-13-2017, 08:17 PM
So, I havent had any issues on my built regarding starting for quite some time, its always been a first crank kinda build..

However recently I changed out my thermostat because with my electric water pump I wasnt running one but even just pulsing the electric pump let the car run colder than I wanted.

So I changed the thermostat and filled the expansion tank and ran the car for 2 minutes. Shut it off and decided to remove the rear coolant temp sensor and fill the block that way with coolant, Once I did that I overfilled that area just a bit, replaced the thermostat and went to crank the car. But it just kept cranking....


Facts.

1. The engine stumbles once under the first couple cranks but then just cranks, This is repeatable every attempt.
2. I have spark
3. Engine sounds normal
4. Spark plugs are dry, Wideband is pegged lean.
5. Fuel pump is on, Fuel rail has pressure.
6. Fuse 34 and 10 are not blown (Fuse 10 was blown but replaced)
7. Tach shows engine speed when engine attempts to fire, so I dont think the crank position sensor is bad.
8. Vag com connects and shows no codes.
9. Confirmed with spare ecus.


At this point I have no idea what could be the cause. Its obviously electrical but all the engine plugs are fine. Thoughts?

walky_talky20
02-13-2017, 08:30 PM
Firstly, nice baseline information there. List format and everything. Nicely done, sir. [up]

Lack of fuel seems like a strong possibility here. I'm thinking it's either trying to start really REALLY lean, or you aren't getting any injector pulse at all.

Easy thing: Try unplugging the Coolant Temp Sensor. If your problem is a faulty temp sensor pegged HOT, you aren't going to get cold start enrichment and it's going to deliver fuel as if you're idling in death valley with an overheated engine (ie: basically no fuel). Unplugging the CTS forces the ECU to use a static temp value - 60C as I recall - and should allow it to fire. It may start hard and/or take a few tries, but should go without too much drama. Alternatively, you could check the Coolant Temp value in the ECU via VCDS to see exactly what that sensor is giving you. My theory here: you broke a wire (or something) whilst you were removing/reinstalling the sensor.

Thing 2: Check that you are getting power and injector pulse at your injectors. I'd recommend a 12v LED test light, but you can also use a 194 automotive bulb or similar. The important thing is not to draw too much power or you can damage the injector drive circuit in the ECU. No headlight bulbs here. My theory: 12v lead to injectors may be broken. Fuse could be good, but power may not be getting all the way to the injectors.

Those are my initial guesses. And please remember I'm not a mechanic. Just some guy on the internet.

Good Luck.

Davdraco1
02-13-2017, 08:53 PM
could it possibly be a primary o2 sensor? I know that has nothing to do with the work you just performed on your car but mine went one day out of the blue. mine was reading way rich so it pulled fuel, so much that it would buck and kick and back fire. Then eventually it wouldn't even start.

andyrew
02-13-2017, 09:33 PM
CTS reads in vag com no issues. Unplugged an no difference.

Injectors are pulsing around 7vlts, 3vlts no crank. Not sure what normal is. I attempted to pull the injectors out of the engine and try and crank to see if fuel came out of them but they just blew out of the rail. Also I stripped the manifold hole trying to get the bolt back into the regulator side ....... So impact down it goes never to come back out again.

Primary o2 is probably 6months old genuine Bosch. Most of the parts on this engine are brand new.


It

Davdraco1
02-13-2017, 09:37 PM
CTS reads in vag com no issues. Unplugged an no difference.

Injectors are pulsing around 7vlts, 3vlts no crank. Not sure what normal is. I attempted to pull the injectors out of the engine and try and crank to see if fuel came out of them but they just blew out of the rail. Also I stripped the manifold hole trying to get the bolt back into the regulator side ....... So impact down it goes never to come back out again.

Primary o2 is probably 6months old genuine Bosch. Most of the parts on this engine are brand new.


It


The primary sensor on my car was about 6 months old and only a few thousand on it. Do you use or have launch control? I think that's what killed mine.

andyrew
02-13-2017, 09:57 PM
I dont think LC is activated. I have about 200 miles on the entire build, been trying to tune the damn car for a year now with two tuners.

Also just went and unplugged the o2 with no difference. Done for the night but keep firing those ideas.


This was the car about 4 months ago (Last time I really drove it.)
http://www.914world.com/bbs2/uploads/post-172-1480624437_thumb.jpg
http://www.914world.com/bbs2/uploads/post-172-1480623890_thumb.jpg
http://www.914world.com/bbs2/uploads/post-172-1480624075_thumb.jpg


https://www.youtube.com/watch?v=ymyGqg5HoTE

knoxsj59
02-26-2017, 05:59 PM
Sounds like my experience on a higher mileage 1.8. Tendency in lifters trapping deposits internally. Also the oil pressure relief valve trapped deposits in spring under valve body. Result is floating over extending lifters in cold conditions causing compression loss in some cylinders due to valves partiality open when initiating starts in colder weather. Try pre warming the oil cooler body with a heat lamp nested by intercooler. Optional is a hair dryer for 1/4-1/2 hr. If the oil is close to normal operating temp. the lifters will pump up normally and car starts. Results prove its time to remove and clean the pressure valve first, and worst case the lifters removed and either popped apart to internally remove deposits, or replace them with new ones. The easy way to determine the symptom is a compression test when cold, and after running with the pre-warming oil cooler/filter body's.

andyrew
02-27-2017, 07:38 AM
Sounds like my experience on a higher mileage 1.8. Tendency in lifters trapping deposits internally. Also the oil pressure relief valve trapped deposits in spring under valve body. Result is floating over extending lifters in cold conditions causing compression loss in some cylinders due to valves partiality open when initiating starts in colder weather. Try pre warming the oil cooler body with a heat lamp nested by intercooler. Optional is a hair dryer for 1/4-1/2 hr. If the oil is close to normal operating temp. the lifters will pump up normally and car starts. Results prove its time to remove and clean the pressure valve first, and worst case the lifters removed and either popped apart to internally remove deposits, or replace them with new ones. The easy way to determine the symptom is a compression test when cold, and after running with the pre-warming oil cooler/filter body's.

Its essentially a brand new engine, all the lifters were gone through and thoroughly cleaned to like new. The issues is very obviously electrical, not mechanical.

I think its a failed crank sensor as it will attempt to start for the first 5 seconds then nothing. Which is exactly how the ECU reacts to a failed crank sensor per the factory manual. If I can get it to start in the first 5 seconds then it runs just fine.

My biggest issue is I have a DBW harness and a DBC block, which requires either a custom adapter or a modified sensor. I modified the last sensor to fit and think that is the reason why it failed prematurely. Im working on building an adapter plug now.

Seerlah
02-27-2017, 11:15 AM
Iirc, only difference between sensors are the grey connectors. I have a not-so-cheap crank position sensor I can send you to test out (need to find in my box-o-shit first). Save cost on ordering it if not needed, but it means extra downtime for you (ie wait for sensor to ship coast to coast, then order new one if it is the case).

It is an Advanced Auto crank sensor I picked up when I was in a pinch. $70...ouch! Ordered a Bosch one for around $40 shipped and that is the story about the spare sensor (not full story).

andyrew
02-27-2017, 01:41 PM
Seerlah,

I appreciate the offer, I have a el cheepo CPS I bought from rock auto, I was going to splice it with the new style but when I cut it open it was 2 wire!!! Chineese POS....

I looked up the wiring diagram and couldnt tell how a 2 wire would work for it. So I hit up pick n pull with some snips and grabbed the older style female connector and 6" of wire, then I cut my old connector and I'll spice the two. Then I'll redo the chineese wire I bought and install it to see if it works.

I'd be more than happy to buy your spare. Is it the later model or newer model?

I'll post a pic of the modifications I had to make to my later model unit as they ARE different. The cutout in the block for the sensor is smaller in the AEB engine than it is in the AWM engine apparently, so I had to make the sensor narrower in relation to the mounting hole and the wire.

BTW Im in no rush. With a baby on the way I rarely ever spend any time on the 914 now.

Seerlah
02-27-2017, 08:50 PM
Never knew there was that difference too. Just learned something new!

Not really trying to sell that extra sensor I have. Paid $70 for it when a Bosch cross referenced one can be sought for around $40-50 (one currently on my block). I would have let you borrow it for free no problem, but I still paid $70 dollars for it and price to buy I would have proposed would have simply been asinine for an Advanced Auto sensor. Would be much better to spend like half what I paid for Advanced Auto Crap, and get a cross referenced Bosch sensor.

andyrew
02-28-2017, 07:53 AM
Did the AA sensor work at all?

Seerlah
02-28-2017, 08:24 AM
Yes, then crapped out on me middle of winter 2-3 winters back on one of the coldest nights that year. Left the car where it crapped out (knew immediately it was the sensor), got picked up, went to house, back to car, took out sensor, trip to Advanced Auto, replaced under warranty, back to car, swapped back in, and drove her home. Mess around till next morning and would have found my car on cinder blocks or something. From a car guy's perspective...night def sucked.

And...still not complete story! Just order a Bosch unit. Double check the cross referenced link is correct. But they can be sought for cheap.

www.amazon.com/Bosch-0261210177-Engine-Crankshaft-Position/dp/B00BJLLW10/ref=sr_1_1?ie=UTF8&qid=1488300117&sr=8-1&keywords=0261210177+bosch

andyrew
02-28-2017, 09:51 AM
I need the early one though. I'll see if I can find one on amazon at lunch. Thats way less than I paid for one at rock auto, which generally is the cheapest that I can find.

Seerlah
02-28-2017, 10:05 AM
I forgot. Sucks looking for this stuff on my cell phone. Laptop broke and waiting for replacement in the mail.

andyrew
03-04-2017, 02:52 PM
OK,

Final update on the no start issue. It looks like it was the CPS. I was able to make it work with the adapter I made.

Side note, The colors on the wires between the early and later are off. The position of the wires on the connectors are 3,2,1, and if you match them up they dont work. 2 is right and it shows correct on the wiring diagrams, but 3 and 1 are flipped between the years. So #3 needs to go with #1 and vice virsa.


If anyone does a DBC to DBW conversion and wants to build a adapter harness for the CPS instead of modifying one.


Another oddity, the 2 wire $40 CPS from rock auto actually worked with the adapter harness.


Now to finish my revised coolant line (Trying to build a usable drain, draining the coolant has been a PITA...) and turn the boost up :)

Seerlah
03-05-2017, 04:51 AM
Good info. What brand sensor? I'll look up the Bosch cross reference when my laptop comes in. Sucks doing everything on my phone.

andyrew
03-05-2017, 05:36 PM
Sensor was an "ultra power"

andyrew
08-25-2017, 12:53 PM
Bump here.

Crank position sensor did not fix it Only worked for that day then quit working and that was a BOSCH sensor. I didnt update this as honestly I just have been way to busy and the car is just making me mad every time I look at it.

I had some bad wires near the coolant temp sensor that I thought was it, but after fixing that I have concluded that is not the case.

I am able to get it to start intermitently, and the RPM guage works fine. I have been having issues connecting my to my OBD port but that was after this started.

Any more possible leads would be great. I have no idea what to do now aside from rip the engine and harness out and go over it wire by wire, which hell it may be a bad wire, or it may be some bad sensor.

Seerlah
08-25-2017, 02:23 PM
I find it odd the crank position sensor made the car run for one day, then back to the bullcrap. As much as it sounds like a waste of time, too much of a coincidence to ignore. I would investigate that particular area more.

andyrew
08-25-2017, 03:59 PM
I've changed out the CPS 3 times as that is what makes the most sense. What I dont understand is I can see the dash showing RPM's under cranking.

Seerlah
08-26-2017, 10:20 AM
Check compression, as much as it bothers me to state the obvious (like you are a knewb). Also maybe spark plugs got soaked on at least a few attempts (again, for some oddball reason)? I am leaning towards a short in your engine harness somewhere. Once again, around the cps region.

andyrew
08-26-2017, 11:24 AM
Not sure if this came across, but It will run JUST fine if I start it dead cold. THEN if I try to start it warm it will not start, or it will take many, many attempts to start it.

Once its running it'll run forever and have perfect drive-ability and power.

Seerlah
08-26-2017, 01:28 PM
Didn't know this. Look into your coolant temp sensor. Maybe a mix of both coolant temp and crank position sensor. Throwing a jab at it, but worth a shot. Logging your coolant temp should let you now.

kjames1270
08-26-2017, 01:36 PM
I have the same issue except car won't start when engine is cold.
I changed the coolant temp sensor which did help for about a week, but back to normal 3-4 cranks. I just use starting fluid. Going to try CPS next as it probably needs a change a anyway.

Sent from my A0001 using Tapatalk

walky_talky20
08-28-2017, 11:34 AM
Andyrew - When it is failing to hot restart, do you have spark? That would be a good thing to check first. If you do not (and I'm assuming you do not), you should check to see what is missing from the coil packs such that they don't fire. Are they missing 12v+, or are they missing the 5v square wave trigger? This will tell you which path you need to go down.

If it has spark, you obviously need to go down the fuel path. So it's important to check it out and start in the right direction.

andyrew
08-29-2017, 08:11 AM
Andyrew - When it is failing to hot restart, do you have spark? That would be a good thing to check first. If you do not (and I'm assuming you do not), you should check to see what is missing from the coil packs such that they don't fire. Are they missing 12v+, or are they missing the 5v square wave trigger? This will tell you which path you need to go down.

If it has spark, you obviously need to go down the fuel path. So it's important to check it out and start in the right direction.


Thanks,

I am fairly sure I have spark as my initial diagnosis above in the first post showed spark. I'll pull a coil pack and check again. I think the issue is the fuel injectors are not firing or they are not firing in the correct sequence.

Heck maybe they just are not throwing enough fuel? Dont know..


Another big issue I have is I cant connect Vag Com right now. Not sure how or why that happened.