Low compression no start

[Recklessb5]

Just put the motor back in after the 0a3 swap and a gates timing belt due to a rip in the old one and I set timing and turned it over by hand and all was fine buttoned it all up stuck the engine back in and finished the swap, converted the ignition to 2.0 coils and crank it and nothing just turns and turns maybe a spudder here and there but no start has fuel pressure and spark then I did a compression test and got 90psi could this be due to missing a tooth on each cam or my tensioner pulling the belt I’m lost

[Silverex]

Could be bent valves...what was compression on each cylinder?

[Recklessb5]

Only tested cyl 4 was at 90psi but I bet it’s the cams out of timing cause there’s no way I bent valves with any compression plus I turned it over by hand and I aligned it with the old belt so it wouldn’t be off enough to bend valves

[vavJETTAw36]

That’s not how you perform a compression test. You should check other cylinders to baseline the test and verify the tool


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[Silverex]

^+2 you gotta test all the cylinders, only testing one doesn’t tell you much.

I was suggesting bent valve(s) from the tear in the old timing belt. Did car run fine before you did any work?

I’d do a compression test on all cylinders, double check your wiring for the 2.0 coils and go from there.

[CELison]

Only tested cyl 4 was at 90psi but I bet it’s the cams out of timing cause there’s no way I bent valves with any compression plus I turned it over by hand and I aligned it with the old belt so it wouldn’t be off enough to bend valves

What does that mean "bent valves without any compression"? You don't do a timing belt by trying to alight marks with old belts. That's how you get it wrong. You either have bent valves or the timing is off and the overlap is causing low comp.

[Recklessb5]

What does that mean "bent valves without any compression"? You don't do a timing belt by trying to alight marks with old belts. That's how you get it wrong. You either have bent valves or the timing is off and the overlap is causing low comp.

"with compression" and i also did a leak down and theres no loss so looking at TB issues its definitely hanging the valves open half way through the compression stroke

[Recklessb5]

and for further notice i didn't do the TB only to the old belt but aligned all the pulleys with the old one on, then removed it double checked all my timing marks and straight edged my cam gears but im guessing since i didn't have it pinned and lock barred i guess it had shifted to advanced the cams when i released my belt tensioner, so im going to do it the right way and pull it and do it with the cam bar and pin like i should have in the first place

[Monty23]

Is the motor coughing and hacking while cranking, or just cranking with no signs of life?

[Recklessb5]

Is the motor coughing and hacking while cranking, or just cranking with no signs of life?

Ive cranked it over about ten times on different occasions in the past two days trying to diag with a scanner on and each crank was for about ten seconds and maybe one or two pops every few trys so there is definitely fuel and spark

[Silverex]

"with compression" and i also did a leak down and theres no loss so looking at TB issues its definitely hanging the valves open half way through the compression stroke

if valves are hanging open and you tried starting it a few times theres a good chance they are bent. I would do a compression test on ALL cylinders and a leak down if you have the tool. Report back with the readings and where the air was leaking out during the leakdown

[CELison]

Doing a tbelt job without a crank pin, cam bar, or popping the cam gears loose before tensioning the belt is a big mistake. How did you verify the timing was correct without the bar? Took the VC off and checked the marks on the cams? If it won't even start because the timing is so off, you probably smoked some valves.

[Recklessb5]

Soooooooooo... for everyone's enjoyment just to note for all those that like to store there nuts in there as.s
I completely re-did the TB job and was way within all the timing marks but just for shi ts and giggles i pinned the crank and lined the cam and chain marks up and slapped it back together still nothing so i did a compression test and all cylinders where at 100-110 psi and the leak down was within 15 percent of each other granted this motor has a hundred and sixty thousand miles, then i went along and checked all grounds and wiring to my coils and individual tested each one and all had more than enough spark, large white hot. so if we could please step beyond the bent valve BS,
i had my scanner on today and got a clear reading of about 170 rpm with a 1000 cca battery on a charger so could a crank sensor still be a chance? i did see a few reading in the past from this same sensor that showed no reading or intermittent readings, im pretty damn lost this motor ran flawlessly this cars been sitting since November in a garage.


One last thing my dumbass forgot about this was a TIP car and when i cleaned and installed the subframe i cut the tip harness could that play any role

[CELison]

Alright you're a little hard to follow. So did you mess with the cam timing in relation to each other or no? You say chain which to me means intake cam time with exhaust cam since the car has a timing belt not a chain. You put the crank pin in, put the cam bar on, popped the cam gears loose, tensioned the belt with the bar on, then sinched the cam bolts down. That correct? Because that's the only way to do it right. And if you did mess with the cams, the arrows on the cam caps need to align with the notches on the cam gears. Sounds to me like your timing is still off or you fucked it up so bad you bent valves.

[Recklessb5]

Alright you're a little hard to follow. So did you mess with the cam timing in relation to each other or no? You say chain which to me means intake cam time with exhaust cam since the car has a timing belt not a chain. You put the crank pin in, put the cam bar on, popped the cam gears loose, tensioned the belt with the bar on, then sinched the cam bolts down. That correct? Because that's the only way to do it right. And if you did mess with the cams, the arrows on the cam caps need to align with the notches on the cam gears. Sounds to me like your timing is still off or you fucked it up so bad you bent valves.

You really got me reeling over here like Ive wasted the past ten years of my life making a profession as a technician, but yes i did the timing as specified, I wouldn't pull the cams to time a motor but sure. So yes i aligned the cam cap marks with the notches in the actual cams then set the pre-tension on the belt then torqued the cam gears. also while were on the topic i did a leak down and the valves are all very happy with there little coronas just chilling in there with there little valve seat buddys, so ive been reading a few other posts about some issues with the fuel pump relay stuck and not sending signal to the injectors.

[CELison]

Your compression is way low. The only time I've seen it that low is when the timing is off or a valve isn't seating. The cams can be in time with each other but off bank to bank. If you never touched the cam timing in the heads those marks are irrelevant and I'm not sure why you're referring to them as your reference for the motor being in time. The bar fitting and the crank being where it should are the only things that matter if you never touched the cams.

[Recklessb5]

Your compression is way low. The only time I've seen it that low is when the timing is off or a valve isn't seating. The cams can be in time with each other but off bank to bank. If you never touched the cam timing in the heads those marks are irrelevant and I'm not sure why you're referring to them as your reference for the motor being in time. The bar fitting and the crank being where it should are the only things that matter if you never touched the cams.

I didn't move the cams the bar was on and the crank was pinned. I don't understand why your still stuck on the valves, i would've found that out with the leak down and the compression is lower then usual cause the engine's dead cold so the rings are way open the pistons are shrunk and its a tired ass motor the the walls are probably washed out but the valves ARE NOT LEAKING so that has nothing to do with the motor not starting. and a hundred and ten psi is plenty to kick a motor over

[CELison]

Ok. You know best.

[Recklessb5]

Ok. You know best.

I'm glad you've seen my world of magic and deductive reasoning don't worry I'll let you know when i find the fuel issue, I'll put my best unicorn on the job.

[Monty23]

Fuel, compression, spark... all at the right time. Compression has been verified as acceptable. 2 to go. I'm still thinking this is related to the 2.0 coil conversion. Have you verified you have proper ignition? Fuel should be easy to check with a$20 gauge installed in the feed line or just pull the line and aim into a bucket and verify flow. No need to overcomplicate this.

[Recklessb5]

Fuel, compression, spark... all at the right time. Compression has been verified as acceptable. 2 to go. I'm still thinking this is related to the 2.0 coil conversion. Have you verified you have proper ignition? Fuel should be easy to check with a$20 gauge installed in the feed line or just pull the line and aim into a bucket and verify flow. No need to overcomplicate this.

Finally a rational person lmao, I do have fuel pressure at the rail i have verified spark to each coil and plug, Im going to try and swap the relay once I get off work I pulled the pump this morning and all was fine so its coming down to the injectors I guess I've just been swamped at work so haven't time to really dive in but at least I can sit on the web during my hours

[CELison]

Dude, I’m not saying your car isn’t starting Bc of low comp, I’m saying the timing issue may be causing the low comp considering this whole thing started by you fucking with the timing. 110 is plenty for a car to start, but still low, even on a cold motor. Good luck chief.

[Monty23]

Something else worth trying is pulling the maf sensor plug and seeing if it will start without the MAF. Could be some sort of tuning or air metering issues (like a leak) as well. Also, since you are a tech you should perform some diagnostic functional checks with your scanner... it would be much faster to narrow in on the problem that way.

And try not to get too bent out of shape with CELison, He is a good dude and knowledgable.

Dude, I’m not saying your car isn’t starting Bc of low comp, I’m saying the timing issue may be causing the low comp considering this whole thing started by you fucking with the timing. 110 is plenty for a car to start, but still low, even on a cold motor. Good luck chief.

It sounds like he did a bunch of stuff all at once. Time to get back to basics and start ruling out all the variables.

[CELison]

People are trying to help you and you're getting butthurt because you think our responses are beneath your skill level. Even though you're the tech who botched a Tbelt job and cut through the trans harness...

[Silverex]

Soooooooooo... for everyone's enjoyment just to note for all those that like to store there nuts in there as.s
I completely re-did the TB job and was way within all the timing marks but just for shi ts and giggles i pinned the crank and lined the cam and chain marks up and slapped it back together still nothing so i did a compression test and all cylinders where at 100-110 psi and the leak down was within 15 percent of each other granted this motor has a hundred and sixty thousand miles, then i went along and checked all grounds and wiring to my coils and individual tested each one and all had more than enough spark, large white hot. so if we could please step beyond the bent valve BS,
i had my scanner on today and got a clear reading of about 170 rpm with a 1000 cca battery on a charger so could a crank sensor still be a chance? i did see a few reading in the past from this same sensor that showed no reading or intermittent readings, im pretty damn lost this motor ran flawlessly this cars been sitting since November in a garage.


One last thing my dumbass forgot about this was a TIP car and when i cleaned and installed the subframe i cut the tip harness could that play any role

Where was the air leaking from when you did the leak down tests??

Crank sensor definitely wouldn’t hurt to swap out especially if you had issues with it in past that probably would have been my first try.
Cutting the Tip harness could be a possibility but I don’t know much about the wiring so hopefully someone else can chime in about that.

Not sure where the hostility is coming from but no one was rude or anything to you. Your posts are very hard to understand and when you use wrong terms like chains vs belt it throws us off even more. Everyone in here is only trying to help

[Recklessb5]

I mean sorry to the liberals but what I had said I thought was pretty clear, but yea ill try the MAF cause i did notice the reading when i had the scanner on live view it wasn't picking up anything but i have no base to go off of unless someone knows off the top of there head and Im getting a out of limits driver reading on the live view for my injectors as if it just cant find anything for either bank but everything else checks out fine all temp sensors, egts, o2 voltages, crank sensor, and tps. ill also back track the TIP harness i didnt think it would effect anything since its just been unplugged dangling under the car in the weather but ill make sure its not grounding out and fucking anything else up

[Recklessb5]

Where was the air leaking from when you did the leak down tests??

Crank sensor definitely wouldn’t hurt to swap out especially if you had issues with it in past that probably would have been my first try.
Cutting the Tip harness could be a possibility but I don’t know much about the wiring so hopefully someone else can chime in about that.

Not sure where the hostility is coming from but no one was been rude or anything to you. Your posts are very hard to understand and when you use wrong terms like chains vs belt it throws us off even more. Everyone in here is only trying to help

Its not hostility, Im just an asshole.

[vavJETTAw36]

You really got me reeling over here like Ive wasted the past ten years of my life making a profession as a technician, but yes i did the timing as specified, I wouldn't pull the cams to time a motor but sure. So yes i aligned the cam cap marks with the notches in the actual cams then set the pre-tension on the belt then torqued the cam gears. also while were on the topic i did a leak down and the valves are all very happy with there little coronas just chilling in there with there little valve seat buddys, so ive been reading a few other posts about some issues with the fuel pump relay stuck and not sending signal to the injectors.

Ooooooh but you’ve already confirmed spark. Or wait, did you really?

Have you checked fuel pressure? Can you share the values?

You say the only issue you found was for the injectors being out of range. Perhaps you can perform an injector test with vcds. It will buzz (lack of better term) each injector.




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[Silverex]

I mean sorry to the liberals but what I had said I thought was pretty clear

Far from it

like Ive wasted the past ten years of my life making a profession as a technician.

Ummm unless your an oil change tech, you did waste the past 10 years. Feel sorry for those customers.

Its not hostility, Im just an asshole.

Ya we can tell

[Recklessb5]

Ooooooh but you’ve already confirmed spark. Or wait, did you really?

Have you checked fuel pressure? Can you share the values?

You say the only issue you found was for the injectors being out of range. Perhaps you can perform an injector test with vcds. It will buzz (lack of better term) each injector.




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i just have to find my cable and i have had zero time to fuck with the car working 60hrs with a kid if you know how that goes.