98 Turbo (re)build

[Black798]

That to me doesn't sound like a misfire, I view a misfire as an intermittent event. It sounds more like a dead cylinder that just isn't firing period. The reason I say that is that it sounds just like my truck did when the cylinder 1 injector died.

Id start by checking the obvious: plugs, wires, coil packs, and injectors. Make sure all the cylinders are actually getting spark and fuel before you go chasing your tail with timing. If all cylinders are getting fuel air and spark then I would start to look at timing. But otherwise its a waste of time. You really shouldn't have to tweak the timing at idle. The computer should be able to manage that even with the different cams and crank.

 

[Coward]

If all 3 timing marks are 100% right then timing shouldn't be the issue. I believe if any of the cams were clocked wrong it wouldn't run as good as it sounds. Like he said the timing isn't adjustable mechanically anyway. That vac line on the back of the drivers valve cover connects to one of the hard lines across the top of the intake plenum. The one closest to the firewall.

 

[jerrydub10]

That to me doesn't sound like a misfire, I view a misfire as an intermittent event. It sounds more like a dead cylinder that just isn't firing period. The reason I say that is that it sounds just like my truck did when the cylinder 1 injector died.

Id start by checking the obvious: plugs, wires, coil packs, and injectors. Make sure all the cylinders are actually getting spark and fuel before you go chasing your tail with timing. If all cylinders are getting fuel air and spark then I would start to look at timing. But otherwise its a waste of time. You really shouldn't have to tweak the timing at idle. The computer should be able to manage that even with the different cams and crank.

So I checked today and cylinder 6 was dead, was getting spark, so I replaced the fuel injector with one from the other intake and it ran a lot better, so I buttoned it up and took it for a drive. Drove about a block before the check engine light started blinking at me and the engine sounded like it was running on 3 cylinders. When I got home I hooked it up to the scanner and had multiple misfires including cylinder 4 and 6. Think I should get my injectors cleaned and put fresh fuel in? The fuel has been sitting in the tank since December.

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[Diezel]

While 6+ month old gas could be an issue. I would be pulling the injectors AND rails and flushing them out. Also replace the inline fuel filter on the frame rail.

 

[jerrydub10]

While 6+ month old gas could be an issue. I would be pulling the injectors AND rails and flushing them out. Also replace the inline fuel filter on the frame rail.

How would I go about flushing the injectors? Besides taking them to get cleaned of course. And thanks for the advice!

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[Black798]

So I checked today and cylinder 6 was dead, was getting spark, so I replaced the fuel injector with one from the other intake and it ran a lot better, so I buttoned it up and took it for a drive. Drove about a block before the check engine light started blinking at me and the engine sounded like it was running on 3 cylinders. When I got home I hooked it up to the scanner and had multiple misfires including cylinder 4 and 6. Think I should get my injectors cleaned and put fresh fuel in? The fuel has been sitting in the tank since December.

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6 month old fuel won't be an issue. I have a 77 Chevy that has at least 6-month-old gas in it that fires up and runs like a top. Modern gas has so many additives it takes a long time for it to go really bad. But before you send the injectors out to be cleaned check the resistance on them by using a multimeter on the two prongs where the wiring harness plugs it.

They should be between 14 and 20 ohms. If they're any higher the coil inside them is bad and cleaning them won't help, you'll have to replace them entirely.

If I had to guess you have 1 or two injectors with bad coils that are causing the misfire. Generally, those injectors will fail intermittently for a bit then just die. Which would explain why it drove for a little then they quit.

 

[Diezel]

6 month old fuel won't be an issue. I have a 77 Chevy that has at least 6-month-old gas in it that fires up and runs like a top. Modern gas has so many additives it takes a long time for it to go really bad. But before you send the injectors out to be cleaned check the resistance on them by using a multimeter on the two prongs where the wiring harness plugs it.

Depends on the source of gas, and how long it was in the tank before "sitting".

As for flushing the injectors, mostly just pull them and look at the screens on the inlet of the injectors.

 

[jerrydub10]

thanks for the info guys! i am debating on just getting a whole new set of injectors, just cause the ones I have have 150K miles and 200K miles on them. i remember reading something about the blue injector being a higher CC, does anyone have any info on it?

 

[gamefreakgc]

thanks for the info guys! i am debating on just getting a whole new set of injectors, just cause the ones I have have 150K miles and 200K miles on them. i remember reading something about the blue injector being a higher CC, does anyone have any info on it?

What cc injectors do you have in there right now? Please tell me they are not stock injectors with a turbo

 

[jerrydub10]

What cc injectors do you have in there right now? Please tell me they are not stock injectors with a turbo

soooooo they are stock injectors, because i was running the 7th injector and only 8psi max. but i think i want to go up to the 400cc injectors when i get the aftermarket ones. That or go bigger and get the FIC6, the only problem is if I get rid of the 7th injector I need a new intake manifold top, since I cut holes and mounted the injector onto the manifold itself. but the new injectors (stock for now) should get here tuesday so hopefully wednesday shes back on the streets, and off the streets if ya know what I mean.

 

[gamefreakgc]

soooooo they are stock injectors, because i was running the 7th injector and only 8psi max. but i think i want to go up to the 400cc injectors when i get the aftermarket ones. That or go bigger and get the FIC6, the only problem is if I get rid of the 7th injector I need a new intake manifold top, since I cut holes and mounted the injector onto the manifold itself. but the new injectors (stock for now) should get here tuesday so hopefully wednesday shes back on the streets, and off the streets if ya know what I mean.

Oh, well if you already ordered more injectors no sense in ordering again. Though if you can return them... you definitely want bigger injectors if you want to run more than 8 PSI. The 7th can support up to 11 PSI on a supercharger, but I've been told turbos are more fuel hungry. How much boost do you plan on running?

I run at 11 PSI with 310 cc injectors and a 225 cc methanol injector. It's enough fuel that I run pretty close to a even 0% at the top end currently (I take out roughly -20% until 4000 RPM, and by redline I'm +10% for my tune) but camshafts and a bigger throttle body are coming soon, so that'll suck up some more fuel.

 

[Diezel]

Oh, well if you already ordered more injectors no sense in ordering again. Though if you can return them... you definitely want bigger injectors if you want to run more than 8 PSI. The 7th can support up to 11 PSI on a supercharger, but I've been told turbos are more fuel hungry. How much boost do you plan on running?

Correct, Turbo's are only "more fuel hungry" in two ways. 1: The intake turbine builds more heat, due to physical coupling to the exhaust turbine. 2: Exhaust Gas temps need to be managed, to help the turbo.

 

[jerrydub10]

Oh, well if you already ordered more injectors no sense in ordering again. Though if you can return them... you definitely want bigger injectors if you want to run more than 8 PSI. The 7th can support up to 11 PSI on a supercharger, but I've been told turbos are more fuel hungry. How much boost do you plan on running?

I run at 11 PSI with 310 cc injectors and a 225 cc methanol injector. It's enough fuel that I run pretty close to a even 0% at the top end currently (I take out roughly -20% until 4000 RPM, and by redline I'm +10% for my tune) but camshafts and a bigger throttle body are coming soon, so that'll suck up some more fuel.

Right now I plan on staying at 8psi but once I get more money for more fuel upgrades I'm gonna go up to around 15psi. And bigger throttle body?? They make those for the 3rd gen?

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[jerrydub10]

Ok guys, I got the new injectors in, and now it runs WORSE!!!! I'm not sure where to go from here besides compression/leakdown testing and timing triple check. I doubt its leakdown since the heads had a professional valve job done while I was building the engine. Does anyone have any idea? Also its not throwing any codes. I havent looked into it since I had to leave the house for errands but im pretty sure tgeres a dead cylinder. I'm about to just take it to the shop.

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[gamefreakgc]

Ok guys, I got the new injectors in, and now it runs WORSE!!!! I'm not sure where to go from here besides compression/leakdown testing and timing triple check. I doubt its leakdown since the heads had a professional valve job done while I was building the engine. Does anyone have any idea? Also its not throwing any codes. I havent looked into it since I had to leave the house for errands but im pretty sure tgeres a dead cylinder. I'm about to just take it to the shop.

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Can't adjust timing on these engines unless the timing marks are off when the belt was put on. Any chance it was put on 180* off? It has happened before.

With a brand new engine it could be so many different things... really hard to say.

 

[jerrydub10]

Can't adjust timing on these engines unless the timing marks are off when the belt was put on. Any chance it was put on 180* off? It has happened before.

With a brand new engine it could be so many different things... really hard to say.

I can take the valve covers off and check the timing marks on the cams, but I'm pretty sure I got it right.

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[jerrydub10]

So I figured out not only is the engine misfiring, its running super rich at idle. The spark plugs are covered in black dry soot. At least in cylinder 6.

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[Maltbytoy]

So what about the buckets and shims being off? You mentioned using the 3vzfe cams, did you grab the buckets out of the 3vzfe heads? Did you set them to 5vzfe specs or 3vzfe?

I have a set that I am thinking off tossing in, just can’t find anyone who has done it successfully yet?

 

[schmauster]

Id check out that compression in #6

 

[jerrydub10]

So what about the buckets and shims being off? You mentioned using the 3vzfe cams, did you grab the buckets out of the 3vzfe heads? Did you set them to 5vzfe specs or 3vzfe?

I have a set that I am thinking off tossing in, just can’t find anyone who has done it successfully yet?

I ended up using the 5vzfe cams. The shop did the valve job using the specific cams that are in it right now.

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