Injector failure?
09-21-2006, 09:45 PM
#1
Injector failure?
Alright I've had DW 500cc injectors for about a year now. All is well and haven't had any issues with them until this past week. I've been getting major hesitation and consistent detonation on the front middle and right cyclinders, initially I thought it was my spark plugs were bad because a week earlier, glennmoormax traded me cars for a day, while he had it my car felt like its running on 4 cylinder and sounded like a Subaru. After that happened, he immediately stop driving it and called me about the issue. It turned out that both the middle and right front cylinder's spark plugs had no gap at all so it wasn't firing, on top of that the tip was a bit whiter than the rest of the plugs that I pulled. I've regapped and it's been fine until today. On the way home, my car became very studdery under partial throttle and I could hear the exhaust note slightly change like it misfiring. I originally thought that the plugs were bad so I stopped by napa and picked up some new NGK 2step colder (been running those since being boosted). Babied it home and I pulled them out, the gap was still .033 but it was extremely white now on the same two cylinders while the others were a darker shade of gray. So after I put the new plugs in, I went for a test drive. Under partial throttle, it was driving normal but when I got on it in 2nd I only saw 5.9 psi on a 8.7psi spring and I had to immediately let off because it started to detonate loudly at about 5700rpm. I dont think I did any damage to the engine but because its detonating at such a low psi and the plugs being white (probably running lean) from those cylinders, the only thing I can conclude is I'm not getting enough fuel under WOT. I'm thinking a failing injector?
Please don't take it as I'm trying to knock on DW, they are a great company and I have already emailed them, awaiting respond. I haven't had problems with them before. BTW I know one of these injectors was bound to be flakey because I broken the half of the casing around the prongs where it plugs into the harness about 6 months ago when I did my DEK. One going bad could very much be my fault even it has work fine for 6 months.
The only other thing that I can think of is put some injector cleaner in there, anything thing else I can do to narrow down the problem?
Please don't take it as I'm trying to knock on DW, they are a great company and I have already emailed them, awaiting respond. I haven't had problems with them before. BTW I know one of these injectors was bound to be flakey because I broken the half of the casing around the prongs where it plugs into the harness about 6 months ago when I did my DEK. One going bad could very much be my fault even it has work fine for 6 months.
The only other thing that I can think of is put some injector cleaner in there, anything thing else I can do to narrow down the problem?
09-21-2006, 10:50 PM
#3
Is that AFR the same as it normally is, or is that leaner than it was before? If your AFR is staying the same then you can't be starving for fuel I'd say.
I wouldn't rely on plugs being white directly after installation as an indication of leanness. I've checked plugs a million times, often very very soon after installing them, and they always start out very very white, so white it has concerned me, but after a little while they get to their normal tan color. It's just part of the process it seems.
Also what's this about the spark plugs having no gap at all when you checked them... I don't understand. Are you saying the ground strap melted to the electrode, or the ground strap was just somehow pushed into contact with the electrode after installation (which would obviously be a problem).
I wouldn't rely on plugs being white directly after installation as an indication of leanness. I've checked plugs a million times, often very very soon after installing them, and they always start out very very white, so white it has concerned me, but after a little while they get to their normal tan color. It's just part of the process it seems.
Also what's this about the spark plugs having no gap at all when you checked them... I don't understand. Are you saying the ground strap melted to the electrode, or the ground strap was just somehow pushed into contact with the electrode after installation (which would obviously be a problem).
09-21-2006, 11:05 PM
#4
Originally Posted by Nealoc187
Is that AFR the same as it normally is, or is that leaner than it was before? If your AFR is staying the same then you can't be starving for fuel I'd say.
I wouldn't rely on plugs being white directly after installation as an indication of leanness. I've checked plugs a million times, often very very soon after installing them, and they always start out very very white, so white it has concerned me, but after a little while they get to their normal tan color. It's just part of the process it seems.
Also what's this about the spark plugs having no gap at all when you checked them... I don't understand. Are you saying the ground strap melted to the electrode, or the ground strap was just somehow pushed into contact with the electrode after installation (which would obviously be a problem).
I wouldn't rely on plugs being white directly after installation as an indication of leanness. I've checked plugs a million times, often very very soon after installing them, and they always start out very very white, so white it has concerned me, but after a little while they get to their normal tan color. It's just part of the process it seems.
Also what's this about the spark plugs having no gap at all when you checked them... I don't understand. Are you saying the ground strap melted to the electrode, or the ground strap was just somehow pushed into contact with the electrode after installation (which would obviously be a problem).
The white tips were from my old plugs which had a lot more miles on it, 5-6k? I havent check the new ones yet. The no gap was not melted rather just pushed in contact with the electrode, maybe by the piston but there wasn't any physical damage to the strap like you would expect being hit but a piston. I'm definately more worried about the detonation issue rather it be a fuel problem or something else. I don't believe its a timing issue because I have ran more boost and under more adverse conditions than this.
It was in the 60's today.
09-22-2006, 02:45 PM
#5
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As I said when we spoke earlier today. Pull your codes, see if you get a specific cylinder code. If you suspect the injectors and get a specific cylinder code try moving the injectors to a different cylinder and see if the code follows them.
Do a compression test. Like I have posted many times about the Z32 MAF & 5xxcc inejctors, running the stock timing like that at even 8psi is always walking a fine line. If I didn't have 93 gas, or if it was above 85 degrees, or if I was heated soaked I would get some detonation.
We are happy to check them out for you, regardless of being out of the warrenty period
Do a compression test. Like I have posted many times about the Z32 MAF & 5xxcc inejctors, running the stock timing like that at even 8psi is always walking a fine line. If I didn't have 93 gas, or if it was above 85 degrees, or if I was heated soaked I would get some detonation.
We are happy to check them out for you, regardless of being out of the warrenty period
09-23-2006, 03:13 PM
#6
well, It looks like it may not be an injector issue. I'm getting fuel, spark and the injector resistance is to spec. Another disturbing thing that I found is I'm getting only 140 in compression in my 6th cylinder (the one with bad plug). Every other one is @170. Looks like this winter I'll be biting the bullet and building a 3.5.
I'm still detonating as of right now, any above 50% throttle and about 3k I would get some studder and detonation. I got a 0905(crank sensor) and a 0701 (mutli miss fire), replaced the crank sensor with a working one, no difference. The CEL havent came back since it was reset. I'm out of ideas on what else I could do.
I'm still detonating as of right now, any above 50% throttle and about 3k I would get some studder and detonation. I got a 0905(crank sensor) and a 0701 (mutli miss fire), replaced the crank sensor with a working one, no difference. The CEL havent came back since it was reset. I'm out of ideas on what else I could do.
09-23-2006, 07:53 PM
#8
Speaking of which, its the first time I put in shell 91. Normally, I put in chevron but where i was at the time, there was no chevron in site. I'm gonna put in some Chevron and after that maybe some race gas if I can fine some this late in the year. track season just ended a couple of weeks ago.
09-23-2006, 10:24 PM
#9
Though I've never *really* been much of a believer in the Brand X gas is better than Brand Y gas (when it comes to the major companies that is), I think that could be a significant piece of information. Who knows, I've never experienced a problem with one brand of gas vs another brand of gas, but that doesn't mean that there aren't differences - maybe my tune is just safe enough (pulling enough timing) that it doesn't make a difference for me. But since you're walking the fine line as mike said, maybe even the slightest difference is enough to put you over the edge. In light of this information I honestly can't believe you haven't had a problem running that much boost on 91 **** water gas up until this time honestly, I figured you were running good 93. Doing what you're doing on frickin 91 is really pushing it in my mind. Mike was running 93 all the time, the few occasions he had to put even 92 in, or if the weather was just overly warm on 93, he'd start to detonate. This is sounding more and more like a setup problem, and less and less like an equipment failure problem.
The above reasons, combined with the supposed fact that gas in the winter months has a different formulation than gas in the summer months might be an issue. I don't know HOW winter gas differs from summer gas, but I've always noticed worse gas mileage in the winter, and I've always heard that there IS a difference, though I don't know what it is. Maybe that is a contributing factor.
If you can't find race gas anywhere, read the thread about homemade race gas in the stickies. Toluene is 118 octane - you can get it at paint stores and such. Mix in some of that in the appropriate proportion and you've got your detonation preventing race gas that can shed more light on this.
On 93 octane what you and mike and other's are (were) doing is walking the line imho, on 91 octane it's even more of an expensive and daring proposition.
The above reasons, combined with the supposed fact that gas in the winter months has a different formulation than gas in the summer months might be an issue. I don't know HOW winter gas differs from summer gas, but I've always noticed worse gas mileage in the winter, and I've always heard that there IS a difference, though I don't know what it is. Maybe that is a contributing factor.
If you can't find race gas anywhere, read the thread about homemade race gas in the stickies. Toluene is 118 octane - you can get it at paint stores and such. Mix in some of that in the appropriate proportion and you've got your detonation preventing race gas that can shed more light on this.
On 93 octane what you and mike and other's are (were) doing is walking the line imho, on 91 octane it's even more of an expensive and daring proposition.
09-24-2006, 01:34 AM
#10
Originally Posted by Nealoc187
Though I've never *really* been much of a believer in the Brand X gas is better than Brand Y gas (when it comes to the major companies that is), I think that could be a significant piece of information. Who knows, I've never experienced a problem with one brand of gas vs another brand of gas, but that doesn't mean that there aren't differences - maybe my tune is just safe enough (pulling enough timing) that it doesn't make a difference for me. But since you're walking the fine line as mike said, maybe even the slightest difference is enough to put you over the edge. In light of this information I honestly can't believe you haven't had a problem running that much boost on 91 **** water gas up until this time honestly, I figured you were running good 93. Doing what you're doing on frickin 91 is really pushing it in my mind. Mike was running 93 all the time, the few occasions he had to put even 92 in, or if the weather was just overly warm on 93, he'd start to detonate. This is sounding more and more like a setup problem, and less and less like an equipment failure problem.
The above reasons, combined with the supposed fact that gas in the winter months has a different formulation than gas in the summer months might be an issue. I don't know HOW winter gas differs from summer gas, but I've always noticed worse gas mileage in the winter, and I've always heard that there IS a difference, though I don't know what it is. Maybe that is a contributing factor.
If you can't find race gas anywhere, read the thread about homemade race gas in the stickies. Toluene is 118 octane - you can get it at paint stores and such. Mix in some of that in the appropriate proportion and you've got your detonation preventing race gas that can shed more light on this.
On 93 octane what you and mike and other's are (were) doing is walking the line imho, on 91 octane it's even more of an expensive and daring proposition.
The above reasons, combined with the supposed fact that gas in the winter months has a different formulation than gas in the summer months might be an issue. I don't know HOW winter gas differs from summer gas, but I've always noticed worse gas mileage in the winter, and I've always heard that there IS a difference, though I don't know what it is. Maybe that is a contributing factor.
If you can't find race gas anywhere, read the thread about homemade race gas in the stickies. Toluene is 118 octane - you can get it at paint stores and such. Mix in some of that in the appropriate proportion and you've got your detonation preventing race gas that can shed more light on this.
On 93 octane what you and mike and other's are (were) doing is walking the line imho, on 91 octane it's even more of an expensive and daring proposition.
I knew exactly what I was getting into in terms of running 8+psi before, but the fact of the matter that is making this situation very puzzling is that I've ran fine before on the same type of gas (chevron 99% of the time) and on again higher boost settings that what I am at the moment. Granted damage could have been done now hence the reason it continues to detonate but from personal experience, I never had any audible detonation like this before even when I was running the same type of gas under both 100 degree temps to near low teens temps conditions.(BTW- most of the time I fill up at the same gas station not only the same brand of gas), I can only go off of what my car has done in the past because there isnt another boosted let alone turbo maximas in the area to compare to. Thats what makes this really weird is everything that I have attempted to test have turn out to be in working operation, the only variable that has changed since the collapsed spark plug incident was the change in the brand of gas and I just remember I ran out of gas last week which just dawned on me today. Another thing that I am going to try is changing the fuel filter which I'm not too optimistic about since if I had a plug fuel filter, I should see a spike in air fuel ratio which I did not see when I datalogged.
I thank you for you help and continue to put out suggestions, I will do my best to follow thru with them until I get this issue resolved.
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