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1G no start, slow crank, low compression, backfires

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enjee

Probationary Member
18
7
Feb 25, 2023
Lavon, Texas
Hello everyone, I have a few questions about my 1g DSM. To catch yall up, I bought the car about 3 months ago for 1k. It had a no-crank problem which was solved by a faulty clutch switch. Other than that a few new parts on the car include; an alternator, mas, spark plugs, fuel pump, fuel filter, battery, and an oil change.

Once I got it to crank I realized it was very slow. I tried using starter fluid to get it going but it caused a backfire in the intake. So I ran a compression test and all the cylinders have 50-60 psi readings.

My question is, Could this be a timing issue? Are my valves bent? Do I check my camshafts?
 
Could be timing. Slow to crank gives me pause too. I would check cams and then, if the cams are aligned correctly, do a leak down test to see why your compression numbers are so low. If your cams are off then you are looking at bent valves. No matter what you are most likely looking at some engine work.
 
Could be timing. Slow to crank gives me pause too. I would check cams and then, if the cams are aligned correctly, do a leak down test to see why your compression numbers are so low. If your cams are off then you are looking at bent valves. No matter what you are most likely looking at some engine work.
Got it, Thank you for the help! I'll keep the form updated on my progress.
 
I'd at least pull the timing covers and check mechanical timing and condition of the belt(s). If not a full t-belt/pulley/WP replacement, especially if unknown age/mileage.
Does it crank any better if the trans is in neutral?
Does your check engine light turn on for ~5 seconds and then turn off when you turn on the ignition?
Double check the order of spark plug wires on the coil.
 
I'd at least pull the timing covers and check mechanical timing and condition of the belt(s). If not a full t-belt/pulley/WP replacement, especially if unknown age/mileage.
Does it crank any better if the trans is in neutral?
Does your check engine light turn on for ~5 seconds and then turn off when you turn on the ignition?
Double check the order of spark plug wires on the coil.
It’s cranks the same in neutral or in gear. Yes, the check engine light turns on them turns off after a few seconds. And spark plugs are in the right order.
 
Been thinking about your "slow crank." You've stated that the battery is new and you bought it with a no crank issue. Any idea how long the car sat without being turned over? Your slow crank could be related to the starter or wiring as well. If the starter is ancient or severely worn (internal resistance) it could be the cause. This would affect your compression numbers depending on how slow the cranking speed is. 50-60 psi is pretty low, but also odd that the numbers are that low across all cylinders. So... if the cams are positioned correctly, check the starter's wiring connections to see if there's anything obviously wrong. And if leak down proves inconclusive, consider removing the starter and having it checked.
 
I ran a compression test and all the cylinders have 50-60 psi readings.
Slow cranking engine speed would cause lower compression test result. You would have needed certain engine speed to run the test. So you shouldn't trust those numbers yet.
 
Slow cranking engine speed would cause lower compression test result. You would have needed certain engine speed to run the test. So you shouldn't trust those numbers yet.

got it, so should i just get a new starter?

Check your grounds, especially the one that connects to the starter bolt.

will do! thank you

Any idea how long the car sat without being turned over? Your slow crank could be related to the starter or wiring as well.

the car has been sitting for almost 3 years. i’ll check the wiring harness first then worry about the camshafts and timing.
 
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got it, so should i just get a new starter?
Just inspect everything and make sure what issue the car has before spending money to get new parts. Like wirings, grounding, valve timing etc. If you are not sure about the timing, set the piston#1 at TDC and take a pic of cam gear's position and upload it here. So we can see it.
 
@enjee - Don't look for a parts solution right out of the gate. The car is 30 years old. Probably safe to say it's been neglected as well since it sat for 3 years because the PO didn't diagnose and fix a clutch switch. A starter is a possibility, but last thing you want to do is replace the starter and end up trashing the engine because of a weak timing belt. Go through things like @DSMPT said. Once you determine that the belts are sound, everything is in time, your wiring and grounds are good, etc. then you can test and maybe replace the starter if the car still has a slow crank. And, yes, that slow of a crank speed would definitely produce low compression numbers.
 
@enjee - Don't look for a parts solution right out of the gate. The car is 30 years old. Probably safe to say it's been neglected as well since it sat for 3 years because the PO didn't diagnose and fix a clutch switch. A starter is a possibility, but last thing you want to do is replace the starter and end up trashing the engine because of a weak timing belt. Go through things like @DSMPT said. Once you determine that the belts are sound, everything is in time, your wiring and grounds are good, etc. then you can test and maybe replace the starter if the car still has a slow crank. And, yes, that slow of a crank speed would definitely produce low compression numbers.
hey, so i removed all the accessory belts and the timing cover. moved the camshafts to TDC and it looks like the oil pump arrow is way off where it needs to be on the. Is this the cause of the slow crank?
 
No. Each of your timing marks could be all screwed up and it won't affect your cranking speed. You'll bend valves and the engine won't run, but it'll crank just fine. The oil pump doesn't have to be aligned anyway.

Again, make sure the timing belt is in excellent condition - no signs of cracking, splitting, contamination, or wear ANYWHERE, and it is tight. If I were you, given the history of the car, I would change the timing belt and water pump now unless you have a receipt proving the belt was very recently done (recently as in the PO had it changed at a shop right before he quit driving it). But first, I would diagnose the slow crank issue.

Your slow cranking is most likely due to weakness in the starting system - low battery power, electrical impedance (poor ground, weak connection, corrosion in the wires), or a bad starter. It is possible you have another issue going on, but the starting system is far more likely. As previously posted, check your wiring.
 
No. Each of your timing marks could be all screwed up and it won't affect your cranking speed. You'll bend valves and the engine won't run, but it'll crank just fine. The oil pump doesn't have to be aligned anyway.

Again, make sure the timing belt is in excellent condition - no signs of cracking, splitting, contamination, or wear ANYWHERE, and it is tight. If I were you, given the history of the car, I would change the timing belt and water pump now unless you have a receipt proving the belt was very recently done (recently as in the PO had it changed at a shop right before he quit driving it). But first, I would diagnose the slow crank issue.

Your slow cranking is most likely due to weakness in the starting system - low battery power, electrical impedance (poor ground, weak connection, corrosion in the wires), or a bad starter. It is possible you have another issue going on, but the starting system is far more likely. As previously posted, check your wiring.
Got it, The timing belt looked pretty worn so i went ahead and ordered a new one. As well as a new water pump. I’ll keep you updated on the progress, and get that starter and electrical system checked out.
 
If it sat for a long time, it wouldn't be a bad idea to pull the spark plugs and get an inspection camera in to look at the cylinder walls before throwing too much time/money at it. Would suck to fix the starting issue and do the timing belt only to find out the cylinder walls are pitted and the engine needs a rebuild.
 
Did you remove ALL of the spark plugs when you did the compression test? If you did, did the car turn over faster when they were out? With the plugs out, there is no compression, and I would think even a weak starter or a starter with a corroded wire would turn the engine over faster. Did the engine turn over faster with all of the accessory belts off? If it did not turn over faster, there is some other drag that is binding up the motor. I can't help but wonder if your water pump did not lock up- if it was leaking when it was stored it certainly could have seized. An idler pulley can do that as well but it is much less likely. Once you get that timing belt off you will be able to rotate the oil pump (and it's balance shaft), the other balance shaft, the water pump, and the two idler pulleys and find what is bound up. I'd put money on it being one of those. Hang in there.
 
Did you remove ALL of the spark plugs when you did the compression test? If you did, did the car turn over faster when they were out? With the plugs out, there is no compression, and I would think even a weak starter or a starter with a corroded wire would turn the engine over faster. Did the engine turn over faster with all of the accessory belts off? If it did not turn over faster, there is some other drag that is binding up the motor. I can't help but wonder if your water pump did not lock up- if it was leaking when it was stored it certainly could have seized. An idler pulley can do that as well but it is much less likely. Once you get that timing belt off you will be able to rotate the oil pump (and it's balance shaft), the other balance shaft, the water pump, and the two idler pulleys and find what is bound up. I'd put money on it being one of those. Hang in there.

i took off all the accessory belts and found that the water pump and the power steering were hard to turn. Also the crankshaft pulley outer ring fell off.

So should I just go ahead and order a new water pump and stuff?

also should i replace the timing belt pulleys too?
 
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The water pump replacement will require you to pull your timing belt apart. This is involved and must be done carefully and correctly. You will want to find a factory service manual or gather information on the procedure in the forum. You are going to want to find a complete timing belt kit with water pump, and preferably a tensioner as well. You can find these kits here:
and from many other sources as well, but I recommend you pay the money to get high quality especially with the tensioner and belt itself. You will also need to pick up a couple of specialized tools- a crankshaft pulley tool for sure, timing cam gear lock, a belt tensioner pulley tool, and tension arm bolt tool, all of which are documented frequently throughout the forum and on VFAQ.com. When you get to this point, do your homework, ask questions, and we can provide links to information you are missing.
 
Okay so after further investigation, i feel like the cam gears are a little off, at least the exhaust one. When trying to adjust the exhaust cam it’s hard to crank it over to the original spot, and it feels like it’s pressing on a valve spring. Could it be on wrong, or is that how it usually is?

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Because of the nature of the valves (their positioning), when turning the cam to align it for putting the timing belt on the cam will want to "slip" away from true center. This is normal. It's also the reason for the timing cam gear tool - a small piece of plastic that gets inserted between the cam gears to ensure they stay in position. Some folks use a crab-type paper clip to hold the belt onto the one cam while using a wrench to align the other gear and slip the belt on. That method works but is more difficult.
 
When you get to this point, do your homework, ask questions, and we can provide links to information you are missing.

Good news and bad news. The good news is the timing has been set and we have no more slow crank, car stutters and seems like it wants to start but it has yet to start.

Bad news is the fuel rail bolt snapped, so I think this messed up the fuel pressure causing it not to start. Getting spark, air, timing, need to check compression, and fuel is going through the line and out the return line but like I said isn’t bolted all the way.

Any advise?
 
I have to ask, did you rotate either cam more than a 1/8 of a turn or so with the belt OFF?
 
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