I recently put a re-manufactured Chevy 350 Long Block Crate Engine in my 1986 Trans Am. For a while, everything ran great. But now I'm having some problems that are starting to annoy me to no end because I can't figure them out. I had a friend help me set the timing, it has a brand new HEI distributor with vacuum advance, new plugs and wires, new-ish Edelbrock carburetor.

Here's a list of everything that I can think of and hopefully they'll be tied to each other. If they aren't, then I'll know where to start and what to do.

1) When the engine is running, the hedder pipe on the #8 cylinder doesn't get hot like the other 7. In fact, I can touch it and it feels slightly warm. Water squirted on 1 - 7 evaporates instantly, but on 8 it just sits there.

I've switched plugs and wires with #'s 2, 4, 3 and 7 and got the same result, #8 not getting hot. I removed the plug from #8 and checked it for spark, and it was present. The plug came out clean and dry, with a little tan ash on it, identical to the others.

2) After I've driven for a while and the engine warms up, the needle shows two lines below 220 on the dash, every time I come to a stop the engine idles very low and tries to shut off. At this point I have to have one foot on the brake and the other on the gas just to keep the rpms high enough to not die, around 500. Once I get going a little the rpms level back to around 500 by itself.

3) Engine diesels when I turn it off after driving.

4) Once turned off after driving, it takes minute or two for the engine to turn back on. Like it doesn't want to catch.

5) When it does finally come back on, the rpms are just around 1550, and when I put the car into any gear the back tires bark and then the engine idles down to zero and wants to shut off. Once again with the two-pedal method.

On a good day, and every day that I first start up the car for that matter, everything seems fine. It starts instantly on the first key turn, Rpm idle is 1000 in park, 500 in gear at a stop. Idle-coasting in drive is 500. It's when the engine gets warm that all the problems start. Except for the #8 hedder not getting hot, that's constant.

Does anyone have any suggestions?

 

You may have multiple things going on.

Hard starts after getting warm/hot would make me think possible starter issues? Does it crank fast or does it crank slow after hot?

#8 not getting hot but has spark present would mean it's not burning correctly. IMO since you have spark then you're lacking proper Air and Fuel or compression.
Are the valves for that cylinder opening and closing correctly?

For your heat issues:
Does this car have air dam present?
Did you burp the radiator after you filled the new long block?
Is the thermostat good?
Is the radiator cap good?

 

Sorry for braking in a line, but i did not want to start a same name topic.
So my question is. Here is a 1987 Firebird, i found 3 unconnected plug under the driver's side dash panel. Can someone tell me where they need to connect? And what they do?
As i figured out the purple/yellow is came from the shifter. (Car is LG4 W8 Auto)

Will wait for any useable answer! Regards.

 

Zuhi:

I believe the purple/yellow are the neutral safety switch off the shifter.

As for the others I don't know for sure and I'm too fat to be trying to crawl under the dash of mine to look. You might have better luck over on the Electronics section.

 

Thank you for replying.

It seems to crank normally after it gets warm, it just takes a few minutes. I'll pay more attention to it next time and let you know.

I don't know about the valves, I'll have to take the valve cover off and have a look. It's been in the low 100's temperature wise here this past month and now we have thunderstorms until next weekend, so it might be a while before I can have a look.

The air dam is no longer there. It had an edelbrock air cleaner sitting on top of the carburetor.

Burping the radiator. I get the basic idea just from the terminology, but I don't know the procedure. I've not heard of that before, so that answer would probably be no. And to my knowledge, the thermostat and radiator cap are good. I'm not having problems with overheating, as soon as the temp gauge goes above 230-ish it drops back down to 220, almost instantly. That to me would indicate the thermostat is working.

 

Will71:

When I bought my car, it was behaving exactly like your symptoms 2-5. Also throw in overheating, dying when hot especially on hot days, and changing gear, or not, when it felt like it. And occasional horrible pinging.

Assume you've got a carb. FWIW, all these problems were gone by the time I had done:

* Replaced the usual service parts with new - plugs, wires, dist cap, rotor, oil, filters, tranny fluid, thermostat, coolant, rad cap & hoses.

* Fixed all the vacuum leaks, like open vac hoses going nowhere, and leaky intake gaskets.

* Ditched the leaky filthy dp Holley with bits missing, and replaced with a clean reco vac sec Holley.

* Replaced the single factory fan that wasn't cutting it, with dual fans and controller. And replaced the air dam. And vented the bonnet. And fixed the leaking rad.

* Replaced the broken tv cable.

* Located tdc, made sure the timing marks were correct, and timed it properly.

* Replaced the dying ignition module in the dist, and the pickup coil (ie eventually new dist). This was a real big one.

* Fixed various intermittent open circuits in the butchered wiring.

For your cool #8 pipe - its at the back, maybe its actually getting a little cooling air flow? Might not be a problem at all. Or like mentioned a mix or valve problem - when accelerating, does it vibrate heaps - ie is the cylinder firing weakly or not at all. Pull the wire and see what difference it makes, then put it back and pull wire from another cyl. The rpm drop should be about the same. If #8 makes no difference, guess theres some digging to do.

 

If your gauge is accurate - thats way too hot, mine starts expiring at 230, and the factory 220 is a joke. Well for Aussie summers anyway. Get that air dam back on and look at your fan situation.

 

I agree that sounds too hot to me. Check your mixture of coolant (they sell little plastic dropper tool to test it at stores) and make sure the coolant is clean looking.

I'm not sure if you understood me about the air dam it's located under the radiator. It's a black plastic flap that diverts air up into the radiator opening. Without it these cars will slowly overheat at highway speeds.

 

The fan is the kind that's run directly from the engine. It's not electric.


The coolant I have in there is the mixture type, part coolant and part antifreeze. When I take the thermostat out is still looks glowy green-yellow.

I did misunderstand. I thought you meant the flat plastic tube that runs from the front, above the radiator, to the air cleaner. I know what you're talking about now, and no, that's not there either. It was missing when I bought the car. I'll have to have a look around in the salvage yards nearby and see if I can find one.

After reading TreeFiddy's post, it dawned on me that when I replaced the distributor and the cap, I still have the original ignition module from the old 305. I'm fairly certain that it's the same one that was put in the car when it was built, by the way it looks. If nothing else, I'll put that on the top of my to get list for the next time I go to the auto parts store.

There's no vibration. But under performance load, there is power loss. When I hit the gas the car will go, until it gets to 4th gear. Then the car wants to die all of a sudden until I let up on the accelerator a little and then the engine picks up again. That only happens when I get on the engine. Under everyday driving conditions, when I'm gentle with it, there's no problem.

One other thing, I had a friend help me try to troubleshoot that issue, and he had me at a dead stop, foot on brake, and the other on the accelerator. Revved the engine enough to feel it start to pull, then pressed it all the way down and let up on the brake... engine died. He's a certified mechanic and has an 85 Trans Am that he's worked on for years, used to work in a garage before he joined the Navy, and he checked everything thoroughly that he could think of and found nothing wrong. He's stumped. Which is why I'm here.

 

Ebay often has air dams too for around $30.

 

Ah ok. I've never seen the engine fan setup on one of these. Is there a shroud that completely closes around the radiator and fan to ensure maximum flow thru the rad? I found this to be essential.

With the engine brake test, and dying at higher speeds - sounds like maybe a fuel delivery problem. Hows the carb - bowl level set correctly? When's the last time it had a full clean or gasket kit? Have no experience with the Edel carbs, but like any other I'm sure there are gaskets that dry out or leak. Or throttle body bolts that can back off and cause leaks and odd behaviour. Did it sit for a long period with no fuel in it?

 

Honestly, I don't know much about carburetors. I don't know how to check anything on them. But yes, it did sit for about a month with no fuel while I removed the old engine and prepped the new one and put that one in. Last week I took the top half of the carb off to see what I could see, and I found 10 fly larvae in the driver's side reservoir, where the floats go. Most of them were tiny, but there was one that was pretty big. I soaked up the fuel in that side with a paper towel and wiped it out and then checked all the tubes that I could get out for clogs but I didn't find anything. I was thinking at the time that it's very possible that one of those could have gotten sucked into somewhere it shouldn't have. I was toying with the idea of buying a book and a rebuild kit to take the thing apart. The carb itself is relatively new. I bought it a year and a half ago to replace the old one that came with the car when I bought it.

 

I was looking through a box of parts in my garage and found a distributor cap with an electronic ignition module in it. It was brand new. I'd forgot I bought it to put on the old engine years ago. So I switched out the one that was in the car, which had a date stamped on it: 11 14 85. I'll see tomorrow what it's like to drive it. But now, the #8 pipe get's hot enough to evaporate water when I tug on the throttle and rev the engine. Sitting at idle, though, it still won't burn off. It will on the other 7, but not that one. Makes me think that there might be a blockage somewhere. Maybe the gasket between the hedder and the block?

 

Ive got a spare air dam. Pm me for price.

 

Just pulled the valve cover off. First thing I noticed is that the cork gasket is soaked all the way through with oil. So that needs replacing. Turned the engine over everything looks like it's moving the way it should. The rockers are good, no clanking sounds. I guess the next step is to take the head off and see what's going on underneath. Ugh. This is getting frustrating. On all outward appearances, everything seems fine. But there's something, somewhere, fouling up the plumbing and I can't seem to find it.

 

Before you go pulling the heads off, cleaning the carb properly would really be a good idea! The slightest speck of muck can block or interfere with a jet or air/fuel passage, some are really tiny. This could cause some of the bad behaviour you listed. How did flies get in the float bowl?!

Need to pull it apart completely and clean all passages, ideally with carb cleaner & compressed air. And fly spray.

I have found that if my Holley sits for a few months with no fuel, the gaskets will dry out/warp, and all sorts of bad behavior results - leaks, stumbling etc. A gasket kit usually sorts it out.

Also recap: what have you done/replaced so far?

 

So far, on this matter, in order:

Checked all fuses.

Switched plugs and wires. Checked for spark (present in all).

Took off the top half of the carb, removed the small tubes, cleaned everything out and put it back together.

Changed ignition coil, cleaned contacts inside distributor cap (they were already clean but I ran a piece of 200 grit sandpaper over them anyway).

Unplugged PCV valve from valve cover, no difference. NOTE: the pcv is right above the #8 hedder, and connects to a T with a breather from above the #1. Then they go into the intake manifold into what looks to me like the #8 exhaust. Pic here: http://i718.photobucket.com/albums/w...P1010725-1.jpg

Removed valve cover, checked valves for movement.

 

Someone on another forum, a local club that i'm friends with, informed me that the driver's side should NOT be attached to that T, and advised on how to fix it for troubleshooting purposes. So here's what I did.

I removed the T, put the (passenger's side, above #8) pcv hose directly into the intake manifold. I zip tied a piece of used laundry fabric freshener onto the end of the hose from the driver's side (above #1). The device that was in there, above #1, is a closed cylilder that has a one-way valve in it, allowing air to travel OUT OF the valve cover (much like the pcv valve, only bigger). So I removed that and wedged a 15mm socket into the rubber grommet, and twisted the other end of the hose into that, so the make-shift filter is on the outside. I snaked that through a hole in the a/c bracket to keep it out of the way and away from the hedder.

After I turned the car on I squirted the #8 hedder with water, and it only took 4 seconds for to burn off. Still not instantaneous, but a HUGE improvement.

I'll be heading out in about an hour and will update how it acts when I get back.

 

The starting issue while the engine is hot could be vapor lock.Are the gas lines routed too close to the manifolds,headers if you have them or the engine maybe?I had that issue and rerouted the lines and put heat sleeving on them,Starts fine now.

 

Where the fuel lines go into the fuel pump (external, mechanical), the one coming from the fuel tank rests up against a metal tube that goes into the rediator. That tube gets hot and I keep pulling the fuel line away from it, and try to wedge it in such a way that it won't touch the tube. It keeps going back tho.

 

If it's an auto transmission more than likely the line that the fuel line is resting on is a cooler line from the trans to the radiator,if it is the send rather than return line it gets quite hot at times.That could be the issue with the hard starting.The fuel heats up in the line and vaporizes.

One more question...Is the fuel line the stock metal line or rubber?

I doubt it's the issue but I always use process of elimination.

 

It is an auto trans. And it is the supply, not the return. the return doesn't touch the tubes. The lines from the tank to the engine bay are metal, then rubber hoses are attached to those that go into the pump. Coming out of the pump is also rubber, then attachs to the metal line going back to the tank. I'll go out and see about zip tying that line away from the tube. Thank you all for your input.

 

Okay here's the test results. The car no longer diesels when I shut it off. The temp gauge in passing gear is 2 lines shy of 220, normal driving it stays at the middle mark between 100 and 220 (160?). It never reached 220. It idles fine at a stop while in gear (stop light). However, it still takes a few seconds to start up. When I got to my destination and turned it off and let it sit for 10 minutes it started like it has been, took a while, then idled at around 500, put in gear and it wanted to die. Drove home, everything was fine again, no idling problems. Passing gear was fine, shifted fine, didn't want to die out. Got home, turned it off. No dieseling. Turn it back on right away, it started no problem. Turned it off, no dieseling. Turned it back on, took a few seconds before it caught. Turned it off, no dieseling.

So that's where it stands right now.

Before I left I cut a length off of the fuel line so it no longer rests against anything.

 

From your description and picture, it looks like you had, in effect, a fresh air breather plumbed thru the T directly to the no.8 intake runner. Though there shoudn't be a hole or fitting there on a carb intake??

The effect of this I should imagine would be to lean no.8 out to the point of not firing, and also upset the mix of other cylinders. Might contribute to a number of your symptoms.

You have now re-plumbed it - basic pcv system should be fresh air into one valve cover, pcv valve out the other, and pipe from pcv valve to the intake manifold directly below the carb.

Or more usually into a fitting in bottom of the carb itself, so the metered pcv signal is mixed with the main carb signal in the small plenum area below the throttle plates.

 

I now have the pcv on the passenger side going into the front of the carburetor, and the fresh air on the driver's side, and I put a cap on the stem coming out of the intake manifold where the pcv line used to go in. So far it's running a lot better now.

Thank you all for your advice and wisdom.