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| Intermittent Cylinder drop http://www.4g61t.org/forum/viewtopic.php?f=6&t=38468 |
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| Author: | jomorris2909 [ Sun Dec 22, 2013 7:36 pm ] |
| Post subject: | Intermittent Cylinder drop |
Sup guys, so I've got my newest Colt up and running for the most part. 4G63, E85, Speed density. Anywho, I know it needs a tune really bad, and that should be coming in the next week or two, whenever the tuner gets an opening. But, right now I'm having issues that I just want to make sure are only due to the tune, so I can have a smooth tuning session and not have to make repairs there. Issues are hard to start, as in long crank times, I'm guessing that's due to the E85 though. And one of the cylinders seems to drop power near completely if it the engine isn't above 2700-3200 RPM. It sounds a lot like it isn't sparking, but I've put new plugs and wires on and still same issue, slightly better though. Once I hit above 3200 though and as long as I'm still on 10-100% throttle, no issues at all, smooth as butter. But if I let off the throttle and let the engine brake, or drop below 3200 the one cylinder starts acting up, sounds like a slight backfire. Any ideas? Is it just the tune? I have an extra coil pack that I'm gonna try out tomorrow and see if it helps at all, maybe the Cam Angle Sensor? Throttle Position Sensor? Any other ideas? Just trying to figure this one out as it's bugging the shit outta me and I don't want to roll into the the tuning shop and have issues with my car besides the tune. First turbo car, and first E85 car, so I'm still learning quite a bit. |
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| Author: | slowdsm [ Sun Dec 22, 2013 7:47 pm ] |
| Post subject: | Re: Intermittent Cylinder drop |
it very well could be the tune but even with e85 it shouldnt be hard to start like that.. mine cranks over about 5 or 6 times before it starts due to my FP not holding back pressure (which im fixing this week also).. when it did hold pressure it would start/restart after shut off almost right away.. have you done a compression test? mine runs great but wont pass emissions.. and I can have it tuned great.. turn car off.. start it to drive 10 min later and tune is off till I drive it a bit... I have 1 cyl thats only about 75 psi.. the rest are 140.... if u have a low cyl... put no more than 1 capfull of oil down in there and re test it.. if it goes up then u have bad rings.. (which is what im replacing on mine this week).. if it doesnt go up... it could be a bent valve.... but a comp test is what I would check first.. Steve |
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| Author: | jomorris2909 [ Mon Dec 23, 2013 2:44 am ] |
| Post subject: | Re: Intermittent Cylinder drop |
It was just at the shop, had them leak down and compression tested nearly perfect across the board forgot to mention that. |
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| Author: | slowdsm [ Mon Dec 23, 2013 2:50 am ] |
| Post subject: | Re: Intermittent Cylinder drop |
well that eliminates that.. how do you know it is down a cyl at times?.. what are the symptoms that make you believe its a cyl drops power? Steve |
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| Author: | jomorris2909 [ Mon Dec 23, 2013 5:56 am ] |
| Post subject: | Re: Intermittent Cylinder drop |
Ok, I wouldn't say it's down a cylinder, but the problem is similar to distributor timing being off a little. Sounds almost exactly the same as my old Colt when it happened. More a pop than a purr on that engine. I can make a video if anyone would like to hear it. Also, keep in mind, it only happens when I'm off the throttle above ~3200, or below 3200 throttle or not. Trying to accelerate below 3200 causing pulsing power delivery until 3200, as if I was tapping the throttle. Soon as I get above 3200, smooth acceleration, no issue, and smooth running at steady speed. Until I let off the throttle and coast in gear, then it goes back to that distributor-timing-off sound while engine braking. Which is why I'm guessing it's the coil pack, or tune. Just searching for any ideas before I start digging in on actual work today. |
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| Author: | thomcasey [ Mon Dec 23, 2013 10:37 am ] |
| Post subject: | Re: Intermittent Cylinder drop |
I have had that issue. Ended up being the coil pack. You may be loosing two cylinders with weak spark. In another case I have seen it with a bad connection to the throttle off/closed switch. It was faulty telling the ECU the throttle was intermittently off/on which kept cutting and starting the fuel. |
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| Author: | Flying Eagle [ Mon Dec 23, 2013 12:32 pm ] |
| Post subject: | Re: Intermittent Cylinder drop |
Check the power transistor terminals, injector terminals, and the coil pack plug wire terminals for an intrusion of the green death. I'm thinking weak coil pack or transistor issues because your ignition switches to a different style of firing around that RPM window where your problem occurs. For the very perceptive you can hear the difference in some cars as you bring up the RPm and cross the threshold. |
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| Author: | slowdsm [ Mon Dec 23, 2013 1:31 pm ] |
| Post subject: | Re: Intermittent Cylinder drop |
I agree with the above.. check the coil pack and ignighter (power transistor) to make sure they have good connections.. also check the injector box.. the silver 1x3" box on firewal with 4 wires coming out of it.. they will have like white heat shrink on the ends going into the box....and 1 more thing I just thought of while typing this.. check and make sure u didnt plug in 2 of the harness plugs to the wrong one.. (been done many times. lol).. *see link below*.. scroll down and look at plug A-58 and B-04. also after re reading this with the new info (and this may sound dumb but ive done it before also).. double check ur firing order... some people get busy doing other things and just plug them in as if they go in order.. (like 1 to 1.. 2 to 2 and so on.) thats not the correct order.. http://www.dsmtuners.com/forums/article ... rness.html Steve |
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| Author: | Flying Eagle [ Mon Dec 23, 2013 2:53 pm ] |
| Post subject: | Re: Intermittent Cylinder drop |
Also recheck timing with the car in the hot map range, with both grounds applied - firewall plug and DRB plug connector. |
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| Author: | Mechacode [ Tue Dec 24, 2013 10:21 am ] |
| Post subject: | Re: Intermittent Cylinder drop |
Try throwing a new coolant temp sensor in, if it's bad it'll be overloading the motor with fuel. |
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| Author: | jomorris2909 [ Thu Jan 02, 2014 3:23 pm ] |
| Post subject: | Re: Intermittent Cylinder drop |
OK guys, so after meeting with the tuner, we're pretty sure the issue is my large 1450cc injectors, since I don't have an Easy Tune box from FIC. Still haven't tested the theory, but I am going to order a set of PTE 1000cc and see if that corrects the low rpm driveability. Will update more. You guys ever heard of issues with 1450 injectors on our cars? |
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| Author: | Flying Eagle [ Thu Jan 02, 2014 4:37 pm ] |
| Post subject: | Re: Intermittent Cylinder drop |
Only if you can't tune them properly or they have issues otherwise. E85 fuel ... is this fuel fresh ??? They tweak to somewhere around E5X in the winter months. You'll have to compensate for that likely. Fuel old and been sitting? Black varnish will clog up the injectors as a byproduct of combustion as some members here and everywhere else have posted. Ethanol is good and bad. |
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| Author: | CSM Shaun [ Thu Jan 02, 2014 4:42 pm ] |
| Post subject: | Re: Intermittent Cylinder drop |
Quote: Ethanol is good and bad.
Pretty much mostly bad unless you buy it by the barrel, are mixing your own or have a fancy-pants system which detects the gasoline/alcohol ratio and automatically compensates.
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| Author: | Broke4speed [ Thu Jan 02, 2014 4:45 pm ] |
| Post subject: | Re: Intermittent Cylinder drop |
Quote: OK guys, so after meeting with the tuner, we're pretty sure the issue is my large 1450cc injectors, since I don't have an Easy Tune box from FIC. Still haven't tested the theory, but I am going to order a set of PTE 1000cc and see if that corrects the low rpm driveability. Will update more. Depends on the age. Older big injectors were pretty crude, and developed issues pretty easily. In 06, the shop 2G was on some ancient 1600s (w/link) and the idle was terrible. Horrible unit to work with. We switched to some 2150s when they came on the market, and the idle became awesome. You guys ever heard of issues with 1450 injectors on our cars? We've also had many issues with ebay stuff, especially those "too cheap to be true" ones. We've actually made the customer get proper ones, since we didn't trust their reliability. |
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| Author: | jomorris2909 [ Thu Jan 02, 2014 8:11 pm ] |
| Post subject: | Re: Intermittent Cylinder drop |
Yea, the fuel is fresh. Been ddriving it here and there gone through 2 tanks. |
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