Newbe needs help find out what is wrong
08-06-2007, 12:38 PM
#1
Junior Member
Thread Starter
Join Date: Jul 2007
Posts: 3
I have an 89 RX7 non-turbo. My son and I bought it for him to drive in the autocross but we can't keep it running. Here are the symptoms:
Hard starting
runs very rich once started and over heats the CAT.
Will not idle
smooths out at about 3500rpm but sputters at lower rpm
no power
slight smoke out of the exhaust
What I have replaced
new O2 sensor
replaced plugs/ air filter
test I have run:
with a warm engine shut off, disconnected the upper 2 fuel injectors connectors and restart, will idle all day without over heating the CAT.
no smoke out of the exhaust
If I plug the injectors connectors and restart but keep the RPM below 3000 it seems to idle ok. Once it goes over 3000 it starts running rough at all RPMs.
I am thinking that there is a short to ground in the upped injectors someplace but I have not found it. I also thought it was the ECU but do not know how to test it.
Any other things that I am over looking?
Thanks
Hard starting
runs very rich once started and over heats the CAT.
Will not idle
smooths out at about 3500rpm but sputters at lower rpm
no power
slight smoke out of the exhaust
What I have replaced
new O2 sensor
replaced plugs/ air filter
test I have run:
with a warm engine shut off, disconnected the upper 2 fuel injectors connectors and restart, will idle all day without over heating the CAT.
no smoke out of the exhaust
If I plug the injectors connectors and restart but keep the RPM below 3000 it seems to idle ok. Once it goes over 3000 it starts running rough at all RPMs.
I am thinking that there is a short to ground in the upped injectors someplace but I have not found it. I also thought it was the ECU but do not know how to test it.
Any other things that I am over looking?
Thanks
08-06-2007, 01:38 PM
#3
Junior Member
Thread Starter
Join Date: Jul 2007
Posts: 3
Originally Posted by teknics' post='879583' date='Aug 6 2007, 01:42 PM
injectors are probably shot and leaking constantly. Hard starting is cause theyre flooding the engine while its off
I'd rec. Replacing them with new high quality ones.
Kevin.
I'd rec. Replacing them with new high quality ones.
Kevin.
08-06-2007, 01:45 PM
#4
Senior Member
Join Date: Dec 2002
Location: Wayne, NJ
Posts: 4,837
79 is a fair price.
After re-reading your post though i sorta think you may be right about a possible short in the injector wiring, mainly because a leaky injector will leak even without a 12v signal. I would say get the car running with the secondaries unplugged and then check the voltage at the injector clips, they shouldnt be getting any voltage at under 3800rpms.
now i rethink again and I have a feeling it is the injectors themselves since you say you can reconnect them and it idles fine until you rev it over 3000rpms, I think ill stick with my original belief that the secondaries are clogged/leaking.
I dont know if theyre rebuildable i know they can be cleaned and blueprinted which I would imagine would fix them (normally they leak from have particles of dirt trapped in the pintle, etc).
check out marren fuel injection and injector.com lots of rx7 guys deal with them, they should be able to help you out, cleaning and blueprinting them is cheap IIRC, and if it was my car i'd get the primaries done while I was at it, kill two birds with one stone and all that.
Kevin.
After re-reading your post though i sorta think you may be right about a possible short in the injector wiring, mainly because a leaky injector will leak even without a 12v signal. I would say get the car running with the secondaries unplugged and then check the voltage at the injector clips, they shouldnt be getting any voltage at under 3800rpms.
now i rethink again and I have a feeling it is the injectors themselves since you say you can reconnect them and it idles fine until you rev it over 3000rpms, I think ill stick with my original belief that the secondaries are clogged/leaking.
I dont know if theyre rebuildable i know they can be cleaned and blueprinted which I would imagine would fix them (normally they leak from have particles of dirt trapped in the pintle, etc).
check out marren fuel injection and injector.com lots of rx7 guys deal with them, they should be able to help you out, cleaning and blueprinting them is cheap IIRC, and if it was my car i'd get the primaries done while I was at it, kill two birds with one stone and all that.
Kevin.
08-06-2007, 02:13 PM
#5
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Thread Starter
Join Date: Jul 2007
Posts: 3
Originally Posted by teknics' post='879588' date='Aug 6 2007, 02:45 PM
79 is a fair price.
After re-reading your post though i sorta think you may be right about a possible short in the injector wiring, mainly because a leaky injector will leak even without a 12v signal. I would say get the car running with the secondaries unplugged and then check the voltage at the injector clips, they shouldnt be getting any voltage at under 3800rpms.
now i rethink again and I have a feeling it is the injectors themselves since you say you can reconnect them and it idles fine until you rev it over 3000rpms, I think ill stick with my original belief that the secondaries are clogged/leaking.
I dont know if theyre rebuildable i know they can be cleaned and blueprinted which I would imagine would fix them (normally they leak from have particles of dirt trapped in the pintle, etc).
check out marren fuel injection and injector.com lots of rx7 guys deal with them, they should be able to help you out, cleaning and blueprinting them is cheap IIRC, and if it was my car i'd get the primaries done while I was at it, kill two birds with one stone and all that.
Kevin.
After re-reading your post though i sorta think you may be right about a possible short in the injector wiring, mainly because a leaky injector will leak even without a 12v signal. I would say get the car running with the secondaries unplugged and then check the voltage at the injector clips, they shouldnt be getting any voltage at under 3800rpms.
now i rethink again and I have a feeling it is the injectors themselves since you say you can reconnect them and it idles fine until you rev it over 3000rpms, I think ill stick with my original belief that the secondaries are clogged/leaking.
I dont know if theyre rebuildable i know they can be cleaned and blueprinted which I would imagine would fix them (normally they leak from have particles of dirt trapped in the pintle, etc).
check out marren fuel injection and injector.com lots of rx7 guys deal with them, they should be able to help you out, cleaning and blueprinting them is cheap IIRC, and if it was my car i'd get the primaries done while I was at it, kill two birds with one stone and all that.
Kevin.
Thanks for the reply and I will check them out.
Scott
08-06-2007, 04:45 PM
#6
Junior Member
Join Date: Apr 2007
Posts: 24
most of these issues are taken care of by cleaning or replacing the injectors
have you checked the ohm resistance in the injectors using a mulitmeter... you should have hi imp injectors. if the are in spec then check the signal while running. your secondary injectors should not be orperating until the 35/3800 RPM range... if there is power going to them under that range then you may have to fix the wiring or ECU
have you checked the ohm resistance in the injectors using a mulitmeter... you should have hi imp injectors. if the are in spec then check the signal while running. your secondary injectors should not be orperating until the 35/3800 RPM range... if there is power going to them under that range then you may have to fix the wiring or ECU
08-06-2007, 06:57 PM
#7
Senior Member
Join Date: Nov 2001
Location: LA, USA
Posts: 1,622
If the secondary injectors are turning on at idle, that means there is some type of current going thru the wires. There should be no current at the injectors clip when at idle till about 3500 rpms. Something is making ground.
08-07-2007, 01:15 PM
#8
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Join Date: Dec 2002
Location: Wayne, NJ
Posts: 4,837
Originally Posted by turborotor' post='879621' date='Aug 6 2007, 07:57 PM
If the secondary injectors are turning on at idle, that means there is some time of current going thru the wires. There should be no current at the injectors clip when at idle till about 3500 rpms. Something is making ground.
see thats what I was contemplating. BUT he said when he reconnects the injectors the car will idle and run fine, then once he revs into the 3-4k rpms range it starts ******* up again.
So Im thinking his injectors are dirty and once they turn on then it causes the constant dripping, when he touches the injector it knocks the dirt a bit and the pintle closes stopping the leak.
but to be safe id double check the connections, even if your injectors arent the problem, theres no harm in getting 20+yr old injectors cleaned and blueprinted, no matter what they need it anyway lol.
kevin.
08-07-2007, 01:50 PM
#9
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Join Date: Sep 2002
Location: Tallahassee, FL
Posts: 5,425
I'd start with cleaning/recalibrating the injectors, rather than immediately buying new ones. I local turbo diesel shop cleaned mine, and they said that these types of injectors rarely break, they just need cleaning and recalibration to run well after many miles.
08-08-2007, 03:26 PM
#10
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Join Date: Nov 2001
Location: LA, USA
Posts: 1,622
Originally Posted by teknics' post='879699' date='Aug 7 2007, 11:15 AM
see thats what I was contemplating. BUT he said when he reconnects the injectors the car will idle and run fine, then once he revs into the 3-4k rpms range it starts ******* up again.
So Im thinking his injectors are dirty and once they turn on then it causes the constant dripping, when he touches the injector it knocks the dirt a bit and the pintle closes stopping the leak.
but to be safe id double check the connections, even if your injectors arent the problem, theres no harm in getting 20+yr old injectors cleaned and blueprinted, no matter what they need it anyway lol.
kevin.
So Im thinking his injectors are dirty and once they turn on then it causes the constant dripping, when he touches the injector it knocks the dirt a bit and the pintle closes stopping the leak.
but to be safe id double check the connections, even if your injectors arent the problem, theres no harm in getting 20+yr old injectors cleaned and blueprinted, no matter what they need it anyway lol.
kevin.
Oh ok, I must of not read that completely.