Microtech hot start issue: please help
#1
hot start issue: please help
Hello All,
I'm having a hot start issue with my FC w/ LT8. It was fine before but started acting up recently and I'm not sure what it is. I replaced my injectors and clips thinking they may be leaking (They were Venoms), but the problem still persisted. A couple of threads I saw lead me to believe that I need to check the CAS, but I'm not exactly sure how to do this.
Symptoms and behavior:
On a cold start, the car starts perfectly without any issues.
On a hot start about 20-30mins after shutting it off, the car will crank for what seems like 7-10 seconds and finally fires up, misfiring horribly. If I give it gas, it will remedy the misfiring faster, but it's still there.
My idle is a little lobe-y; it bounces between 900-1100. I'm running 750cc primaries.
Proposed solutions:
Check and make sure my CAS is working properly. As referenced here: https://www.rx7club.com/showthread.p...ight=steve+kan . Steve told this gentleman to replace his CAS and it solved all of his problems. How do I check if mine is bad? I've searched on inspecting the CAS and can get a replacement, but I want to make sure the replacement I get is in good shape or know whether or not to even replace mine. I've been told recently that the timing is fine.
Replace fuel filter. I don't really think this is the problem but I'm going to do it anyway for good measure.
Any help or input you guys can give will be greatly appreciated.
Thanks,
Jaime
I'm having a hot start issue with my FC w/ LT8. It was fine before but started acting up recently and I'm not sure what it is. I replaced my injectors and clips thinking they may be leaking (They were Venoms), but the problem still persisted. A couple of threads I saw lead me to believe that I need to check the CAS, but I'm not exactly sure how to do this.
Symptoms and behavior:
On a cold start, the car starts perfectly without any issues.
On a hot start about 20-30mins after shutting it off, the car will crank for what seems like 7-10 seconds and finally fires up, misfiring horribly. If I give it gas, it will remedy the misfiring faster, but it's still there.
My idle is a little lobe-y; it bounces between 900-1100. I'm running 750cc primaries.
Proposed solutions:
Check and make sure my CAS is working properly. As referenced here: https://www.rx7club.com/showthread.p...ight=steve+kan . Steve told this gentleman to replace his CAS and it solved all of his problems. How do I check if mine is bad? I've searched on inspecting the CAS and can get a replacement, but I want to make sure the replacement I get is in good shape or know whether or not to even replace mine. I've been told recently that the timing is fine.
Replace fuel filter. I don't really think this is the problem but I'm going to do it anyway for good measure.
Any help or input you guys can give will be greatly appreciated.
Thanks,
Jaime
#5
I highly doubt it's the injectors as they're brand new Fuel Injector Clinic injectors that haven't even had 1k miles of use yet. Same behavior prior to swapping them out, pretty much identical. I just got the fuel filter so I'll install that tomorrow and let you know how it goes. Thanks again!
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#9
Well, here's my cranking and idling datalog. Sometimes it will do the same behavior even on the first start of the day. It misfires like crazy until the AFRs slowly start to drop to around 10-11. Upon first fire, I have to crank for a little bit longer to get it going on its own and if I leave it idling without giving it some gas, it will die until the AFRs get to around 10-11 then it will idle nicely but a little bouncy. If I rev it from 2-2.5k after initial fire, it will get to better idle quality faster, since this causes the AFRs drop quicker. It seems that I'm running lean at initial crank and for whatever reason giving it more gas will slowly but surely drop the AFRs until it idles nicely.
I can take a video of it soon, when my camera comes in so you can see the RPMs, AFRs and hear the misfire.
Please help! Let me know if there's an easy way for me to get my maps off the microtech and uploaded here.
Thanks.
#10
Also, here are some screencaps if that helps any:
http://i17.photobucket.com/albums/b6...screencap1.jpg
http://i17.photobucket.com/albums/b6...screencap2.jpg
http://i17.photobucket.com/albums/b6...screencap3.jpg
http://i17.photobucket.com/albums/b6...screencap4.jpg
http://i17.photobucket.com/albums/b6...screencap5.jpg
http://i17.photobucket.com/albums/b6...screencap6.jpg
http://i17.photobucket.com/albums/b6...screencap7.jpg
http://i17.photobucket.com/albums/b6...screencap1.jpg
http://i17.photobucket.com/albums/b6...screencap2.jpg
http://i17.photobucket.com/albums/b6...screencap3.jpg
http://i17.photobucket.com/albums/b6...screencap4.jpg
http://i17.photobucket.com/albums/b6...screencap5.jpg
http://i17.photobucket.com/albums/b6...screencap6.jpg
http://i17.photobucket.com/albums/b6...screencap7.jpg
#12
Thanks again for the help
#13
Just wanted to update the thread:
Seems like the problem this whole time was my FPR. The diaphragm was leaking, causing unmetered fuel to be dumped into my intake manifold. This was the explanation for the lumpy idle and hot starting issue. It was basically dumping fuel into the intake when I turned the car off and I'd have to let it sit for a LONG time to get it unflooded, hence why I thought it was a "hot start" issue.
Thanks to everyone that tried to help.
Jaime
Seems like the problem this whole time was my FPR. The diaphragm was leaking, causing unmetered fuel to be dumped into my intake manifold. This was the explanation for the lumpy idle and hot starting issue. It was basically dumping fuel into the intake when I turned the car off and I'd have to let it sit for a LONG time to get it unflooded, hence why I thought it was a "hot start" issue.
Thanks to everyone that tried to help.
Jaime
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