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Have you done a compression test? And what do you mean the plug was covered in black? The part that goes into the combustion chamber was black, or the part that the plug wire goes on to? If it’s the part that’s in the combustion chamber, I would bet that you have a stuck open injector (which will cause a misfire).

Coming from diesel Mercedes I’ve learned that bad mounts are a symptom of shaking, not a cause of it. You will feel shaking from a miss even with all brand new mounts, and replacing mounts on an engine that has issues causing it to shake will just destroy the new mounts.

Have you done anything with the injectors at all? Injector cleaner? Check spray pattern?
 

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1995 gmc safari rwd.
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Discussion Starter · #23 ·
Have you done a compression test? And what do you mean the plug was covered in black? The part that goes into the combustion chamber was black, or the part that the plug wire goes on to? If it’s the part that’s in the combustion chamber, I would bet that you have a stuck open injector (which will cause a misfire).

Coming from diesel Mercedes I’ve learned that bad mounts are a symptom of shaking, not a cause of it. You will feel shaking from a miss even with all brand new mounts, and replacing mounts on an engine that has issues causing it to shake will just destroy the new mounts.

Have you done anything with the injectors at all? Injector cleaner? Check spray pattern?
Hi, i dont have time to do a compression test, it my work van.
Yes, the part that was black is the one that goes inside the engine.
I have not done anything to the injectors, but that does make sense. Maybe the injector of that s. Plug is not delivering fuel to that particular spark plug.
Should i replace all injector since im gonna be replacing one?
Thanks.
Thank you so much for your input.
 

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1995 gmc safari rwd.
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Discussion Starter · #24 ·
I just ordered the spider injector super expensive ($300).
I already dumped like $1500 replacing parts here and there. This will be the last time i throw money on it.
 

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I would warrant a guess that the injector on that cylinder is stuck open and just flooding the cylinder with fuel.

I believe you have to replace all injectors as a unit. I would pull everything apart and see what kind of spray pattern you have.
If you weren’t getting fuel on that injector the plug would not be black. The black is spot/carbon/unburned fuel that is fouling out the spark plug causing a misfire.
 

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I just ordered the spider injector super expensive ($300).
I already dumped like $1500 replacing parts here and there. This will be the last time i throw money on it.
Do some diagnostic instead of just throwing parts at it. That gets really expensive really fast. Us forum members can only take guesses at the problem.
 

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Discussion Starter · #27 ·
I would warrant a guess that the injector on that cylinder is stuck open and just flooding the cylinder with fuel.

I believe you have to replace all injectors as a unit. I would pull everything apart and see what kind of spray pattern you have.
If you weren’t getting fuel on that injector the plug would not be black. The black is spot/carbon/unburned fuel that is fouling out the spark plug causing a misfire.
I agree with you. I think one of the injectors is not working the way it should be.
I ordered the injectors replacement that comes like a central unit and branches out to all 6 cylinders.
When i did the full tune up, everything looked like it was the originals parts. But this particular spark plug was the worst one of them all.
Like u said, if that particular spark plug is fouling out, taking the injector out of the question, that means it is not getting spark and or enough o2?
So far, the parts i ve replaced are:
Spark plugs
Spark plug wires
Distributor assembly (the entire part)
Tps
 

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1995 gmc safari rwd.
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Discussion Starter · #28 ·
Do some diagnostic instead of just throwing parts at it. That gets really expensive really fast. Us forum members can only take guesses at the problem.
Problem is that i dont have the time to do any diagnostics cuz i use the van for work, so i dont have time. At this point im just doing a elimination process.
Ive paid 1500 for the truck a year ago, fully aware that it was a pos but i was like, ok i think i can fix it.
Money is not the issue, the issue is that i want to fix it. Its like a challenge to me. Kinda like a hobby.
But it is kicking my *** so far, which makes me fix it more like an obsession at this point.
 

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Assuming all the parts you replaced are good, it sounds to me like either the injector on that cylinder is stuck open (giving a constant supply of fuel/too much fuel), or the injector is worn and has a terrible spray pattern, where it is just squirting fuel into the cylinder and not atomizing it properly, causing it to not get burned.

Either way, the spark plug is getting fouled because of the injector. Assuming your ignition system is working correctly, and you have no internal engine damage, and taking into account the black spark plug on one cylinder and the misfire, I would feel comfortable assuming that you have an injector issue. I personally would probably do a little more diagnostic before dropping $300 on a new spider but I’m not you 🤷‍♂️

How many miles are on your van?
 

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1995 gmc safari rwd.
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Discussion Starter · #30 ·
Back when ive got the van,i knew it was a pos but i was like, if i replace parts with new ones here and there, at the end, i would have a new van .
Ive spend 400 bucks on a "moog" full front suspension set that i have not put on yet cuz of the shaking issue.
I do really like the van
Assuming all the parts you replaced are good, it sounds to me like either the injector on that cylinder is stuck open (giving a constant supply of fuel/too much fuel), or the injector is worn and has a terrible spray pattern, where it is just squirting fuel into the cylinder and not atomizing it properly, causing it to not get burned.

Either way, the spark plug is getting fouled because of the injector. Assuming your ignition system is working correctly, and you have no internal engine damage, and taking into account the black spark plug on one cylinder and the misfire, I would feel comfortable assuming that you have an injector issue. I personally would probably do a little more diagnostic before dropping $300 on a new spider but I’m not you 🤷‍♂️

How many miles are on your van?
The van has 151k miles.
Im just going to replace the injectors cuz it just make sense to me, based on the research ive done and the info i get from here and yours.
There is no internal engine damaged, the engine sound and feels ok. It just feels like something is holding it down from producing power. Like one component is missing. Say that one cylinder that is dragging down the other 5.
Based on my experience fixing motorcycles, i do concur that it may be a bad injector.
The van is running on 5 cylinders at this point.
 

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Yeah it does not shake at idle.
But you originally wrote:
95 safari v6, it shakes a lot when in gear and waiting at the light with brakes on...
So it only shakes when "idling in gear", not when "idling in neutral".
This is not uncommon. Fresh motor mounts typically help absorb the vibration.
Oddly, mine did this for a short period of time.. then it smoothed back out on it's own.
Maybe new injectors will help.. good luck

Otherwise.. just put it in neutral when sitting at a light.
That's what I normally to do. Problem solved
 

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If you have one carbon fouled spark plug, chances are the poppet is stuck open. Usually running a couple tanks of gas with a bottle of Techron will straighten it out.

If not, make sure you ordered the correct spider. It has to be the CPI, the CSFI and MFI units will not work in a '95.

Camera accessory Audio equipment Cameras & optics Rim Auto part



You have to replace the nut kit also. Otherwise it WILL leak.

Product Automotive lighting Font Bicycle part Cable
 

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Discussion Starter · #35 ·
But you originally wrote:

So it only shakes when "idling in gear", not when "idling in neutral".
This is not uncommon. Fresh motor mounts typically help absorb the vibration.
Oddly, mine did this for a short period of time.. then it smoothed back out on it's own.
Maybe new injectors will help.. good luck

Otherwise.. just put it in neutral when sitting at a light.
That's what I normally to do. Problem solved
Lol that is just what i do, just put in in neutral.
It does have new motor and tranny mounts.
But it is misfiring for sure, 2 dif. Mechs confirmed that.
Also, today i replaced the ignition coil. It help a little with the shaking but no power on the freeway.
 

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Discussion Starter · #36 ·
If you have one carbon fouled spark plug, chances are the poppet is stuck open. Usually running a couple tanks of gas with a bottle of Techron will straighten it out.

If not, make sure you ordered the correct spider. It has to be the CPI, the CSFI and MFI units will not work in a '95.

View attachment 285321


You have to replace the nut kit also. Otherwise it WILL leak.

View attachment 285320
Mmm interesting, u talking about those little bottles that clean the injectors?
Thanks.
 

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Discussion Starter · #38 ·

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I think it works pretty well. I use a bottle every 3 or 4 months just for maintenance and haven't had any problems.

It wouldn't hurt to run the first bottle through on a half a tank just to get things moving but after that it's best to follow the directions.
 
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