Help! Stumped by ignition trouble in my ‘84
Thread Starter
7th Gear
Joined: Mar 2021
Posts: 7
Likes: 0
From: Lake Barrington, IL
Help! Stumped by ignition trouble in my ‘84
All,
looking for some expertise here, because I’m stumped! I have an ‘84, bone stock ~12k miles. Last summer, the typical hard start when it was warm got to be very bad, so over the winter I replaced the ignition control module and capacitor, and it worked perfectly…for about 1 month/75 miles. Now, it won’t start at all, even when completely cold (which was never a problem). I ordered a new ignition control module thinking perhaps I got a bad part, but it made no difference. When I try to start it, I can get it to run (poorly) if I heavily feather the throttle, but it will not idle and sometimes even backfires. Looking for some help here to get it back running again. Thanks in advance!!!
looking for some expertise here, because I’m stumped! I have an ‘84, bone stock ~12k miles. Last summer, the typical hard start when it was warm got to be very bad, so over the winter I replaced the ignition control module and capacitor, and it worked perfectly…for about 1 month/75 miles. Now, it won’t start at all, even when completely cold (which was never a problem). I ordered a new ignition control module thinking perhaps I got a bad part, but it made no difference. When I try to start it, I can get it to run (poorly) if I heavily feather the throttle, but it will not idle and sometimes even backfires. Looking for some help here to get it back running again. Thanks in advance!!!
Melting Slicks
Joined: May 2014
Posts: 2,897
Likes: 592
From: New Port Richey FL
Get a 5' +- piece of hose or a way to pull a fuel sample from the bottom look for water ( your car is a carpet queen 400 miles a year average), I know what you're saying my gas is good but is it(you don't go through that much gas). Next if you put a splash of gas into the intake does it run smooth for a moment, if so your ignition seems ok
In the brief moments it runs do you see spray coming out of the injectors
In the brief moments it runs do you see spray coming out of the injectors
Thread Starter
7th Gear
Joined: Mar 2021
Posts: 7
Likes: 0
From: Lake Barrington, IL
Get a 5' +- piece of hose or a way to pull a fuel sample from the bottom look for water ( your car is a carpet queen 400 miles a year average), I know what you're saying my gas is good but is it(you don't go through that much gas). Next if you put a splash of gas into the intake does it run smooth for a moment, if so your ignition seems ok
In the brief moments it runs do you see spray coming out of the injectors
In the brief moments it runs do you see spray coming out of the injectors
Melting Slicks
Joined: May 2014
Posts: 2,897
Likes: 592
From: New Port Richey FL
Sta-bil can take the Boom out of your gas, yes in a lawnmower,boat it really doesn't matter much because it will get though it and the gas is replaced quickly. In your case you're topping off with the leaves changing and if lucky put a 1/2 tank in by The 4th so that's a 1/2-1/4 tank of old in the mix possibly cycled 3 times with some old.
Thread Starter
7th Gear
Joined: Mar 2021
Posts: 7
Likes: 0
From: Lake Barrington, IL
Sta-bil can take the Boom out of your gas, yes in a lawnmower,boat it really doesn't matter much because it will get though it and the gas is replaced quickly. In your case you're topping off with the leaves changing and if lucky put a 1/2 tank in by The 4th so that's a 1/2-1/4 tank of old in the mix possibly cycled 3 times with some old.
Le Mans Master
Joined: Aug 2017
Posts: 6,943
Likes: 1,490
From: New Jersey
If you have a dial back timing light you should be able to "freeze" the injector pulse from the pod by shining it at it. It shouldn't be light but rather pretty heavy flow from each pod. Just visually looking at it can be deceiving without the light. (Had this problem on a tbi truck. Looked fine until you hit it with light and then you could see how thin the stream was)
And when you say fuel pressure was fine... what is fine? Was it running when you did this?
Was a thermal paste used under the new ICM? If not that's an easy way to cook a part.
The feathering of the throttle is a clue too. Backfires are usually lean though they can be rich too. I imagine if it was that rich you'd smell it.
And when you say fuel pressure was fine... what is fine? Was it running when you did this?
Was a thermal paste used under the new ICM? If not that's an easy way to cook a part.
The feathering of the throttle is a clue too. Backfires are usually lean though they can be rich too. I imagine if it was that rich you'd smell it.
Drifting
Joined: Nov 2018
Posts: 1,767
Likes: 648
From: USA
Have you ever changed the fuel filter? Definitely wouldn't hurt! Also, is there any pressure building up in the tank, is it venting properly through the charcoal canister? If it hasn't been done recently or ever (with only 12K miles), the first thing I'd do is remove the fuel filter and try to blow through it/replace it!!!👍
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Thread Starter
7th Gear
Joined: Mar 2021
Posts: 7
Likes: 0
From: Lake Barrington, IL
If you have a dial back timing light you should be able to "freeze" the injector pulse from the pod by shining it at it. It shouldn't be light but rather pretty heavy flow from each pod. Just visually looking at it can be deceiving without the light. (Had this problem on a tbi truck. Looked fine until you hit it with light and then you could see how thin the stream was)
And when you say fuel pressure was fine... what is fine? Was it running when you did this?
Was a thermal paste used under the new ICM? If not that's an easy way to cook a part.
The feathering of the throttle is a clue too. Backfires are usually lean though they can be rich too. I imagine if it was that rich you'd smell it.
And when you say fuel pressure was fine... what is fine? Was it running when you did this?
Was a thermal paste used under the new ICM? If not that's an easy way to cook a part.
The feathering of the throttle is a clue too. Backfires are usually lean though they can be rich too. I imagine if it was that rich you'd smell it.
For fuel pressure: I taped a fuel pressure gauge to the windshield and went for a drive(measuring pressure under normal and heavy throttle). This was last year so I don't remember the exact readings, but I do remember them being in spec on what this forum suggested as I wrote that off as the culprit. With that said, I did go ahead and buy a new fuel pump to have on hand as I know they have a lifespan and the sock is likely filled with gunk.
I don't have a timing light but will try to borrow/buy one at some point (but probably need to get the car to run at least a little without me in the drivers seat doing crazy things to the throttle to be able to test, right?)
Have you ever changed the fuel filter? Definitely wouldn't hurt! Also, is there any pressure building up in the tank, is it venting properly through the charcoal canister? If it hasn't been done recently or ever (with only 12K miles), the first thing I'd do is remove the fuel filter and try to blow through it/replace it!!!👍
Thanks again to all who are helping me sort this!
Burning Brakes
Joined: Sep 2017
Posts: 941
Likes: 169
All,
looking for some expertise here, because I’m stumped! I have an ‘84, bone stock ~12k miles. Last summer, the typical hard start when it was warm got to be very bad, so over the winter I replaced the ignition control module and capacitor, and it worked perfectly…for about 1 month/75 miles. Now, it won’t start at all, even when completely cold (which was never a problem). I ordered a new ignition control module thinking perhaps I got a bad part, but it made no difference. When I try to start it, I can get it to run (poorly) if I heavily feather the throttle, but it will not idle and sometimes even backfires. Looking for some help here to get it back running again. Thanks in advance!!!
looking for some expertise here, because I’m stumped! I have an ‘84, bone stock ~12k miles. Last summer, the typical hard start when it was warm got to be very bad, so over the winter I replaced the ignition control module and capacitor, and it worked perfectly…for about 1 month/75 miles. Now, it won’t start at all, even when completely cold (which was never a problem). I ordered a new ignition control module thinking perhaps I got a bad part, but it made no difference. When I try to start it, I can get it to run (poorly) if I heavily feather the throttle, but it will not idle and sometimes even backfires. Looking for some help here to get it back running again. Thanks in advance!!!
Thread Starter
7th Gear
Joined: Mar 2021
Posts: 7
Likes: 0
From: Lake Barrington, IL
All: Here's an update! First: A HUGE thank you to all those who suggested a fuel issue. It honestly wasn't on my mind because I evidently had the blinders on focusing on ignition given the recent fixes. However, I sprayed some starter fluid into the intake and finally got it to idle! So, I am narrowing to either fuel deliver or a fuel quality issue. Because it's infinitely easier to install a new fuel pump than figure out how to dispose of ~15 gallons of old gas, I'll install the new fuel pump/sock I bought a few months back and hope that is the issue. If not, I'll go through the fun of figuring out how to store and dispose of a 3/4 full tank full of nasty gas!
Again: A huge thanks to all who helped!
-Max
Again: A huge thanks to all who helped!
-Max
Melting Slicks
Joined: May 2014
Posts: 2,897
Likes: 592
From: New Port Richey FL
Check with your local county recycling center, odds are they have a oil dump, I'm not saying to dump a 15 gallon load but you could move it over a couple of months, as for the storage that could be worked out.
Even if you bought the large Oil drain pan from AutoZone or Amazon plus a couple of non transparent jugs you could probably do the whole move. They don't really mind some gas into the system just don't overwhelm it.
Even if you bought the large Oil drain pan from AutoZone or Amazon plus a couple of non transparent jugs you could probably do the whole move. They don't really mind some gas into the system just don't overwhelm it.
Le Mans Master
Joined: Aug 2017
Posts: 6,943
Likes: 1,490
From: New Jersey
Nearly no recyclers take gas as it's considered hazardous waste. Some recycle centers may do a few dates a year where they will take it and it is lumped into household waste materials... so check that. Most places hate when you add it to the oil tank and they do get docked if it has too much fuel in it so don't do that.
When we get called for remediation of old fuel, it typically gets burned off....
Also, check the pulsator on the fuel pump in the tank, I've had a few of those rupture. The car will kind of run but it won't stay running. They don't like ethanol.
When we get called for remediation of old fuel, it typically gets burned off....
Also, check the pulsator on the fuel pump in the tank, I've had a few of those rupture. The car will kind of run but it won't stay running. They don't like ethanol.
Thread Starter
7th Gear
Joined: Mar 2021
Posts: 7
Likes: 0
From: Lake Barrington, IL
All,
Quick update on this: I replaced the fuel pump and voila: fired up! The weird thing about this is: I've never had a fuel pump stumble before failing, my experience has been they are work or don't...but not this time! Either way: Hope this thread can help someone in the future.
Now that its running, i've identified a very high idle (1500-1600 rpms). Inspected for unplugged/cracked vacuum hoses, I found some gasket material in one of the TBIs, so I'm hoping fixing that will fix my high idle.
Thanks again all!
Quick update on this: I replaced the fuel pump and voila: fired up! The weird thing about this is: I've never had a fuel pump stumble before failing, my experience has been they are work or don't...but not this time! Either way: Hope this thread can help someone in the future.
Now that its running, i've identified a very high idle (1500-1600 rpms). Inspected for unplugged/cracked vacuum hoses, I found some gasket material in one of the TBIs, so I'm hoping fixing that will fix my high idle.
Thanks again all!
Melting Slicks
Joined: May 2014
Posts: 2,897
Likes: 592
From: New Port Richey FL
It's hard to hear but if you're lucky it Whistles, but check the edges of the intake top, that whole flat plate that holds throttle bodies comes off and I have seen a few develop cracks. Under the cover it's a very thin wall and 40 years who knows but I saw them leak in 4 years