I have a fresh rebuilt engine.
I can't get this thing to start at all. Once in a while I get a small backfire.
I'm getting gas, spark, air, and compression.

This engine mostly sounds like it's not even trying to start.

When I installed the timing chain I lined it up dot to dot. I'm not sure where the pistons were at that time. I'm not even sure if that matters. Helms doesn't make any mention of it.
I've lined up 0 degrees with both valves on 1 closed. The rotor is pointing at cyl. 1. At this particular time I'm not sure where the timing sprockets are located.
I've tried it at this point and get the above symtoms. I've tried it with the distributor at 180 and also get the same symptoms. Seems no matter where I put it I get the symptoms.

What could be the problem? I've been banging my head against the wall for 3 days now and have yet to figure it out. What do you guys think?

It's an 88 355 TPI.
BTW - it ran before rebuilding the engine. Also has new cap, rotor, module, pickup coil, wires, and plugs. The computer isn't giving me any codes. My laptop is also not showing me anything that looks out of the ordinary.

 

How do you know you have gas? Sounds like your not getting nearly enuf. Thus the ocasional backfire but no starting.

 

I can smell it. The plugs are also soaked in it. I've changed them twice now while trying to start it. I also have 43 psi at prime.

 

find out whats soaking the plugs. I couldnt start my car for **** when they were bad.

Nate

 

They're soaked in gas.

 

Something similar happed to me when I had a head gasket blow. Turns out, my fuel pressure reg. was bad. One cylinder had a ton of fuel in it! It would not turn over??? I took out the plugs and no. 6 just had about 10cc's of fuel in it! Repalced the regualtor and it solved the problem. Check the fuel psi. regulator bladder.

 

assuming everything is correctly installed with it dot to dot it should be firing on the number 6 cylinder, if you dropped the dist in then with it pointing to num 1 your 180 out but it sounds like you turned it over to num 1 and did it correctly.....

 

dot to dot is firing on #6, either time it off #6 or turn the crank and cam gear both straight up and it'll be fring on #1

 

I've tried both 6 and 1 and a couple of teeth each way. I get the same thing. It mostly doesn't sound like it even wants to fire. All I get is an occassional pop.
Would it make a difference if I got to TDC 6 compression stroke and set the distributor that way? Or am I just making busy work for myself?

Regulator's good. It's not leaking.

 

Are you changing the plugs or just drying them? Fuel soaked plugs will not fire even when they look like they should.

 

Changing. I'm on my 3rd set now. It's starting to get expensive.

 

you need to check your fuel pressure. IF it is high, take off the top of the plentum, then check your fuel psi diaphram. I'll bet that is the problem.

 

When I prime the fuel system I get 43 psi. Perfect.

 

how about when you try cranking it?

 

to correctly check the fuel pressure, you must have the engine running. Unplug the vacume line to the regulator and plug the line off so you don't have a vacume leak. That will show you your pressure.

 

that would be all well and good but his problem is he cant get it running.

 

I'm just guessing, the problem sounds like it is timing/ignition related. Of course I've never messed with very much fuel infected motors, it sounds like the distributor needs to be moved a couple teeth.

 

Snake Squisher,

Forget about your fuel pressure. It is right within the specification for a static (non-runing) test.

IIRC, the '88 TPIs still used the MAF, and an external EST system module. If so, find and unplug the EST bypass connector. You'll get a SES lamp, but you'll at least have full control over the timing advance.

About the timing set you used, was it a three-way set? That is, does it have three keyways broached in the crank sprocket?

Staying warm?

 

Are you sure the valves are adjusted correctly?

 

IIRC the fuel pump won't pump anymore after prime until the engine fires. So checking fuel pressure while cranking would be meaningless. Am I wrong?

The valves aren't set correctly but they are extremely close. I set final lash when the car is running. This insures to me that all the lifters are fully pumped up. Besides, I followed the helms manual to the letter last time and found that every single valve was too tight.

You are correct. 88 still had MAF with a separate knock module. I'll try it disconnected but wouldn't disconnecting the timing wire do the same thing? Also, how would full control of timing allow me to start it?
No 3-way. It's just the single sprocket set with a regular chain.
I'm glad I insulated my garage. :lala: heat!!

I'm thinking either my distributor is bad or a wire to some sensor may have been pinched. What sensors are required to start an engine?

 

now you can turn the dist degree by degree and see what happens.. if someone else is cranking you should be able to get a really good idea as to where your dist belongs.

 

Viper,

Your problem is starting to sound very similar to a problem I had a few years ago. I tried everything, every test I could think of, checked all the parts 3 times. Finally, in desperation, I tried a new computer and BANG, she fired. Upon inspection it looked like it got wet!!!

I don't know if that could be an issue for you, but if you have a friend with a similar year and equipment car, ask to borrow the computer and try it...

Good luck...

 

Have you verified that you're getting good cranking spark? May want to pull the coil wire off the distributor, hold it close (about .25") to a ground point with someting non-conductive and see if it arcs to ground. If it doesn't then you know you have either a bad module or a bad coil.

If it does arc, you'll probably have to re-verify your distributor position with respect to the crankshaft position. Take your #1 plug out (in fact, take out all of your plugs so you can crank the engine over by hand) and slowly crank the engine over until you hear air blowing out the number one spark plug hole. This indicates that you're on the compression stroke for #1. The other way is to watch the #1 rocker arms to indicate when both intake and exhaust valves are closed. Then, as you continue to crank the engine over, watch the mark on the damper and bring it around to 0° BTDC. Now that the engine is on #1 TDC, take the distributor cap off and see what plug wire the rotor is pointing to. If necessary, simply move the plug wires around until #1 is correct, or remove the distributor and alter it's position by a tooth or two. Your engine should now be correctly set up.

 

I'm about ready to try every single tooth in the distributor.
I have good cranking spark. Just tested the coil last night and it passed with flying colors.
All I have for computers is a 91 Z and 92 GTA. Being MAP I would assume they wouldn't work.
If I'm pulling a code 12 from the ECM does that mean it's working or could there still be a problem with the brainbox itself?
Here's a thought.....distributor reference pulses. Do they get sent to the computer or somewhere else first? Maybe it's not pulsing or they're not getting to where they need to go.

hmmm.

 

Yeah, MAP computers will not work on a MAF car.

Code 12 indicates normal operation. Computer is apparently detecting no malfunctions- though I'll never bet my life that a code 12 means there really ARE no malfunctions.

Computer uses the dist ref pulses to time the injectors. Since you appear to be getting fuel into the cylinders, I'll assume this functioing correctly.

You've verified the coil is firing, now what happens if you pull a spark plug wire off the spark plug and hold it close to ground? Do you still get a spark? Do this on a couple of plugs.

Hopefully when you put the timing chain back on, you got the correct positional relationship between the cam and crank. Though, I'm not sure if it's possible to mess that up given the cam dowel and crank keyways.

 

Did you change cams when you rebuilt your engine?? It is a Rare occurance, but it is possible that your cam may have been ground wrong or the dowel pin installed in the wrong position. That would throw everything way out...

Like I said, Rare, but I have seen it once in a friend's engine. Cam was a Blue Racer, which I believe is made or owned by Crane. No dis to Crane here cause I used to run one of their cams with much happiness.

 

Try moving the igniton wires 1 position clockwise on the distributer . firing order18436572.maybe. It worked for me.

 

I do still get spark with the plug boot close to a ground.

I did change cams. The one I'm using is the biggest stock one that came in the 3rd gen f-bodies. 88 350 AT I believe. Don't remember for sure. Got the info out of the tech articles.

One thing I did notice is that while setting lash the nut on intake 5 is much farther up the stud then the rest. I can see through one of the oil return holes and am able to verify that the pushrod is sitting in the lifter. Could this be an indication of a mis-installed cam?
The more I can't fix this the less sure I am that the cam is in correctly. One of the dots was hard to see. IF the cam was installed wrong would TDC 1 as indicated by the balancer and the valves on cylinder 1 being both closed tell me if it was?

What do these cars use for a cam/crank sensor?

 

If it were several degrees off, the lifters might still be on the base circle of the #1 cam lobes. In that case, your cam timing would be off a little. But I'd suspect you'd still be able to get it started. However, (and I'm not sure this is even possible) if you had the dots 90° (or some other way off value) to eachother rather than lined up, it would be so far off that it wouldn't start or run.

If you have a dial indicator you could do the following check and a check spring to replace your valve spring as well as if you know the lobe lift on the #1 intake cam lobe and the valve events (lobe centerlines vs crankshaft degrees), you could check to see if the #1 intake lobe centerline is in the correct position. I'm not sure where you'd find that cam information. But if you did you could save yourself tearing the engine apart if you do the following:

Set the engine to #1 TDC (or 0 crankshaft degrees) (damper mark at zero, might be off by a degree or two). Exchange the #1 intake valve spring for the check spring (it's a lot lighter and won't depress the plunger in the lifter). Put the rocker arm and pushrod back on until there is no up-down play on the pushrod and put the dial indicator on the pushrod side of the rocker arm. You'll probably want to pull out all of the spark plugs since you'll have to rotate the engine by hand to follow what I write below.

When the engine is at #1 TDC, the engine is on the power stroke. Both valves are closed. About when it gets to BDC (half of one crank revolution from TDC), the exhaust valve opens, starting the exhaust stroke. After one more half crank revolution (engine at #6 TDC), the exhaust valve closes and the intake valve should start to open starting the intake stroke. This is about where you should be watching the dial indicator. You should see the max intake lift (which indicates the intake lobe centerline) right about when the engine is at #6 TDC or 180 crankshaft degrees (the exact value will be in that cam info I told you to get). After another half crank revolution, the intake valve will close and put the #1 cylinder on the compression stroke. One more half crank revolution will close the intake valve and put you back at #1 TDC for the power stroke again. Your cam should follow this scenario pretty closely.

 

make sure your spark plug wires are where theyre supposed to be!!

if the whole set is off by one post.....it happens man :/

I bet thats what it is too!

 

Maybe youve dont this but, my freind had the exact same problem. He ended up having the right firing order, but he went around the distributor backwards with his wires...

 

I'd pull all the plugs, and set the initial timing. that way teh engine will be cranking fast enough to get it right , wtih out fouling the plugs quickly, or giving your starter a work out. Then I wouldrun a compression test on all the cylinders, it sounds like you adjusted the valve lash incorrectly. On a fresh motor, it should be high, and within 10% of each other. You should now what to do, based on the result of that test. if the compression is low, either your rockers are so tight, the vavles won't close, or your cam timing is off. I'd bet on the vavle lash. but, your initial timing should be set so your motor can run.

if all that checks out, I'd blame it on the voodoo computer. Joe

 

And if it were that far off TDC1 on the balancer and both valves for cyl 1 would not be closed?
I'm trying to determine if I should tear down to check the cam timing. I don't have a dial indicator.


My wires are on correctly. I marked 1 on the cap before I removed them. It fires clockwise looking at it from the front of the engine.

My valve lash is set to 0 lash without any extra turns. Last time I did the extra turn deal my valves wouldn't close. I fine tune once the car's running.
This is insane

 

One more thing.
Let's assume my cam isn't timed correctly. If I shoot starting fluid into it and turn it over will I destroy anything?

 

Yikes, I'm hesitant to hazard a guess on that one. You might hydraulic the cylinder if you put too much.

One thing, it is possible to check your cam timing without tearing down the engine, and it might prove to be easier than what I mentioned above. Just remove the timing chain cover, bring the engine around to #1 TDC and see where the dots are.

You probably have one of those neoprene, resealable oil pan gaskets, which will make this a lot easier too.

Bring the engine around to #1 TDC. Take the water pump, crank pulley, and balancer off. Take all of the oil pan bolts out except for a couple in the rear. Drop the front portion of the pan. Remove all of the timing cover bolts and pull it off- be gentle with the front seal! You can now see if the dots are lined up or not. If they're not, simply take the timing chain off, losen all the rocker arms and rotate the cam until you get the dots lined up. You don't even have to pull the lifters out!

 

i wouldnt use to much starting fluid!!!! iyt dries out the lubrication.I would try a squirt bottle with gas.

 

If your plugs are fuel fouling, check the temp sensor (the one the ecm uses.....) if it has failed, poor connection, etc, the computer thinks it is -40*C outside, and quite literally DUMPS fuel into the cylinders. Instant flood.

Good Luck

 

Exaclty what I had to do, my dot's were perfect, so that ruled that out for my z.

 

I'm nearly at the point of checking the cam timing.
If I don't have any luck tonight I'll be tearing into it tomorrow.

I'll check into the suggestions. PLEASE let it be one of them.

 

hey i have almost the same problem on my car after a head gasket replacment, i think maybe my valves are too tight because my car cranks for like 2 mins before turning over and then i hear noise from the valves, maybe the valves are your problem. Sounds like alot of people are guessing.

 

Do you have a degree wheel, piston stop, and dial indicator? That would make checking the cam timing a little less labor intensive.

 

I may have found the problem. I always thought that the crank sprocket should be on 0 not 4A or 4R. I don't know how I brought it to the shop but in order to get my crank sprocket to place the key facing cyl 1 on the compression stroke, I need to have the crank sprocket on 4 retard. Is this correct?

 

So, you DO have a three-way timing set! Otherwise, there would be no 4A nor 4R timing installation points. In addition, there should be three keyways, with the associated markings for +4 and -4 degrees. Clearly mark the keyway and timing dot you are going to use before you install the timing chain, then install it like this:



Set it for dead zero and run it, ubless you're REALLY sure you want to advance the valve timing even more.

I'll bet your crank sprocket is about as confusing as this one:

 

That was the problem. :lala:
My sprocket isn't even marked for zero nor is the timing mark for 0 easy to see. When I timed it I obviously lined it up with the wrong timing mark. It runs!
Now on to figuring out why the oil pressure crap is going nuts.

Thanks all for the help :hail:

 

Good. You've solved that problem, so I don;t have to load up a degree wheel, indicator, mag base, crank socket, hub puller, installer, etc....

What's the deal with the oil pressure, or should this be another thread since my dial-up doesn't like these longer threads? Don't do it just for my sake, though.

 

Cool!!! :lala:

Glad it worked out for you!

Good luck.

 

There might be no problem. Once I got the timing straightened out I started the car with the following disconnected:
MAS
no water pump
no front cover
no balancer
no intake tubing
loose oil pan

When cranking over the oil pressure would top out at 60 but as soon as the car started it would drop back to 0. I was looking at some wiring diagrams and it almost looked like the MAS needed to be connected in order for the oil sending unit to operate properly. Not sure if I was reading it right. I messed around with the wire that hooks up to the sending unit and hooked everything back up and now the pressure stays pegged at 60. On the first rebuild it didn't. I am getting good oil pressure at the rockers so I'm not worried anymore at the moment. I have yet to actually drive it out of my driveway so I don't know if the pressure will drop.
I'll start a new thread if need be.

Balanced engines sure run smooth :lala: