My car won't start, need new ideas as to why
 

Ok folks,
for those of you who have not read my introduction thread. I am in the middle of trying to fire up my car after a motor swap. We got an 87 LG4 305 out of a caprice for free and I went about swapping all the parts that we would need for the performance and the ease of installation into the 84 Trans Am. In short...the LG4 could barely be called an LG4 anymore as we installed all the original L69 305 HO equipment we could without touching the internals. Now that I've got everything hooked up and in the car I've been trying since the summer whenever I was home to get it running.

I've replaced the wires, plugs, rebuilt the whole distributor with new parts, fresh battery, and timed it to 6 degrees BTDC on the compression stroke, being a carb car it obviously has air. It will pop out of the exhaust but it won't run. I know I have 7 year old gas and that it won't run on it but I've been using starter fluid or fresh gas straight down the carb. I also have a vacuum leak but even with that it should run.

Does anyone have any ideas as to what it could be? I am on the verge of having the local mechanic get it running while he was sucking the old gas out (mom won't let me do it in the garage). I am only looking for ideas but I won't be able to try them until May. If anyone has any questions as to what else I've done then feel free to ask.

Thanks in advance.

look for stupid mistakes. My friend had problems getting his motor started and it ended up being the distibutor 180 degrees out. so double check eveything and def start with fresh gas. drop the tank may also be worth to replace it if its been sitting awhile

i would also check to c if ur getting spark....u may have a short somewhere. my car had a short to ground in the ignition system n it would crank all day but it wouldnt run. hope things work out

You can hear the engine pop out the exhaust when you crank it so I have to have spark, especially after I replaced all the ignition parts short of the distributor shaft and magnets themselves.

69Bird: I caught that when I first put in the distributor when it was on the stand. Also the way the cap and distributor meet can only be done in one way due to a notch, as well as the wiring location for the cap. (HEI Distributor) so it sort of rules out the distributor being 180 degrees out. Unless you mean the shaft itself, which would make no sense whatsoever.

Plus the classic symptom of the dizzy being 180* out is a backfire out of the carb, not the exhaust.

I'm thinking gas is a big concern. After 7 years I would drop the tank to properly drain it and clean it out or just replace it all together.

- Justin

check stupid mistakes first. one time my car wouldnt start after replacing my head gaskets because i put the wrong plugs on the wrong cylinders.

Agreed. Just double check and even triple check every single thing that is ignition related. Check for shorts. Check to see if you are getting sparks. Drop and flush the tank, and get in some fresh fuel.

Not sure if this was a common issue, since my first mechanic experiences were with my old LG4, but pump the gas pedal when starting... i had to do that to get mine started.

I was using the distributor out as more as an example but something that shoudl always be checked.

I'm not too sure if you went down as far as changing the cam but it sounds like the same problem that i had with my swap. Sounds like your cam may be out of time by 2-4 degrees.

Not a bad thought....but we kept all the internals the way they were. Didn't change a thing as the motor only had 80,000 old folk driven miles on it. I basically swapped everything but the block, heads, internals, and intake manifold. All the accessories were swapped out for the L69 accessories, fuel pump, water pump, carb, distributor, etc. We did everything we could to keep it simple, as we already had to change it from an auto to a manual to get it in the Trans Am as the Trans Am came with an L69/T5 from the factory. We also wanted to keep as much as the original wiring sockets and etc that we could as we didn't want to screw around with the TA's wiring. I've rebuilt the distributor, timed it over and over again, dumped fresh gas and starter fluid in the carb etc. same result. I can't do anything until I get home in May. But keep the ideas coming folks.

A shot of starting fluid down the carb's primaries will confirm or rule out the fuel quality. If it starts on ether, your problem is fuel delivery...either bad gas or no gas. If it won't start on ether, you're down to spark, compression, and timing.

It definatley makes sense. Have you checked to see if you have spark by cranking it with a plug out where you can see it? The distributor can also be off besides 180 degrees. The best way to do it is to put the timing mark on TDC, and rotate the slot in the block with a long screw driver. I believe thats actually the oil pump you are turning. Make it face the #1 piston. Make sure you have plug number 1 starting in the spot that faces the number one piston. If it wont start with gas down the carb its definatley an ignition problem so i wouldnt rule out anything or say it doesnt make sense just yet. Pops out the exhaust can also be the timing too far advanced, and out the carb being too far retarted. My l69 car wouldnt start for the longest time because it had a blown head gasket. Popping out the exhaust and had fuel and spark. Go figure

What do you mean long screw driver in a slot in the block? I'm turning the engine using a wrench on the crank. I know it can be off but I should be able to fix that if its close enough with via rotating the cap. I have it timed to the factory specs for the L69 ignition system of 6 degrees BTDC. Part of the problem I am having might be the fact that we built a hybrid motor out of an LG4 and my L69 to get the car back on the road so it won't fall apart until I get the money to rebuild the original L69.

From what I am seeing and hearing it sounds like (besides the 7 year old gas in the tank) it is a distributor spark timing issue. I just can't nail it down to the right point for it to run.

It probably doesn't have anything to do with your issue, but exactly what parts did you swap off / out of your L69 and onto the LG4 that is currently in the car?

- Justin

start simple. you have 7 year old gas and are pouring gas and starter fluid in the carb. get the straightened out. its like replacing a flat with two bald tires and no jack.

im thinking maybe something isnt interchangable..

This is what we swapped:

All this stuff is from the original L69

Exhaust manifolds
fuel pump
carb
water pump (due to belts and fact that we were keeping the original electric fan)
distributor
AC Compressor
Oil Pan
Power steering pump
smog pump
Oil filler cap
Crank Belt Pulley
Air cleaner and ram air assembly
thermosat
and finally some sensors because of the plug differences and our desire not to hack up the Trans Am's wiring harness. Most of this stuff was swapped so all we had to do was use all the Trans Am's stuff.

I believe that covers all of it. The rest is the LG4. And from what I heard elsewhere, all the stuff I did were common things that people did to soup up an LG4, and all of them should not cause any problems.

I did measurements and checked everything before actually installing everything to make sure it would fit. Therefore I don't think there are any parts issues.

There isn't much difference between them....and everything should be compatible.

http://www.chevyasylum.com/tech/L69vsLG4.html

- Justin

i was just curios i have head of people swaping heads that didnt line up and weird stuff like that

so have you checked for spark yet? with any carb no start issue, thats always where you start. Take the plug out and put it against something metal. (Dont touch it) and have someone crank the car. Just try turning the distributor 180 degrees and reassembling the cap and plug wires exactly where you have them now. its worth a try

I was looking at that list of differences....there is an error on there. They did change the heads and the intake manifold. At least on the 87. The 84 L69's intake manifold didn't fit when we tried to use it. Apparently they changed the angle of the holes that the bolts thread into or something. Just a thought.

I will double check for spark when I get home at the end of may so I can cross that off the list for the Mechanic to check. He brought up things like the engine being seized which it obviously is not because I can turn it with a wrench. Before I take the car to him I will go through it myself and cross out each possible thing he might check. But I will have him do the timing because he might have some better tools to do that. I was wondering if I could use a timing light when cranking it to find out if it is sparking at the right time. All the cases I've used it was with the engine running. I'll keep on trying when I get home in May. Now I have to get back to work on my Thesis presentation...but if anyone has any other ideas (assume that fuel and spark are not a problem), please feel free to throw them out there.

Thanks guys.

They didn't offer an L69 in '87 (when the heads changed), so the chart is still correct. The center intake bolt holes for 87+ heads are on a different angle (with the exception of the aluminum L98 corvette heads).

- Justin

Maybe I should get some L98 heads then....that will solve all my problems and I have a hell of a HP gain :rofl: Not. I know the stopped using it in the f-body after 86 but I think they kept it for the Monte Carlo didn't they?

blown head gaskets, broken timing chain, wiped out cam lobes, huge vacuum leaks(like brake booster line) valves hanging up or broken/bent, cracked head/block (although youd be losing coolant). Check for milkshake in your oil just to be safe. Just a few things besides fuel and spark. And yeah montes had l69s till 88. I believe every small block changed when they changed the heads over, i could be wrong though. The l69 will fly with a few bolt ons. My camaro had a real HEI distributor(vac advance), a holley 600 or something, performer intake, small tube headers and a few other small things. 5 speeds came with the 3.73s, that combo with the higher-than-normal-305 revving motor, made for a very fun car

I think you just gave me the answer.........a vacuum leak was one of them I was considering....I think it is the brake one you mention, that might not be hooked up. But like I said...I can't try anything til I get home after graduation in May....which is annoying. The chevy V8 changed from a two piece to one piece rear seal in 1987 and I think that effected some other changes as well. That change alone gave me a hell of a time finding the right clutch for the swap.

I agree with the 5 speed and 3.73 gears, I was just looking at an old Motortrend...imagine my shock when I found that the numbers generated by the L69 with that drivetrain combo was equal to a contemporary Porsche 928 to 60 and the 1/4 mile, and faster than a Corvette, Ferrari 308, and Jaguar XJS V-12, all of the same vintage as the 84 L69 with the T5 and 3.73s or 83s to those same figures :shock:. In all fairness though, the vette was an automatic.

With the 87 LG4 I think I have a 9.3 compression but I don't know. I thought I had an 8.6 until someone said it was 9.3. The engine came out of a Caprice so I do have reason to believe it was 8.6. But if it is a 9.3 motor I won't be losing too much power compared to the original motor.