Boost and stalling issues
08-12-09, 10:17 PM
#1
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Boost and stalling issues
I recently installed a used engine in my FD after I cooked a coolant seal. Everything was doing great for about a week untill now. I got these 2 problems that are most likely not related.
First, I get poor boost. I only get about 3-4 PSI max, on the primary or secondary turbo. I don't hear anything like a big wooshing sound that a boost leak would do, so I was thinking of a wastegate jammed open. could it be something else? my rats nest hoses have all been checked before putting the engine in. Last owner says the turbos were rebuilt a year ago.
Also, my engine stalls randomly. When I get into neutral at a red light or a stop, the engine just dies sometimes. It doesnt get flooded or anything, and it starts perfectly after. I can litteraly shut the engine down by getting into neutral reving a little. When I take my foot off the pedal, The revs will simply go down to zero.
It only happens when the engine is hot, but it doesn't happen all the time.
mods: downpipe, intakes, lightweight flywheel, running premix.
First, I get poor boost. I only get about 3-4 PSI max, on the primary or secondary turbo. I don't hear anything like a big wooshing sound that a boost leak would do, so I was thinking of a wastegate jammed open. could it be something else? my rats nest hoses have all been checked before putting the engine in. Last owner says the turbos were rebuilt a year ago.
Also, my engine stalls randomly. When I get into neutral at a red light or a stop, the engine just dies sometimes. It doesnt get flooded or anything, and it starts perfectly after. I can litteraly shut the engine down by getting into neutral reving a little. When I take my foot off the pedal, The revs will simply go down to zero.
It only happens when the engine is hot, but it doesn't happen all the time.
mods: downpipe, intakes, lightweight flywheel, running premix.
08-12-09, 10:22 PM
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Rotary Ninja
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I'm assuming you have a stock ECU since a PFC/Haltech/etc. isnt listed in your Sig, but correct me if im wrong. have you noticed if the engine is stalling while you have lights on, AC running, fans running? anything like a heavy electrical load, etc?
08-12-09, 10:28 PM
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Yes, I have the stock ECU
I assume the rad fans were working when the stalling problem occured since it's pretty hot outside and I was not on the highway, and I was listening to music on the stock bose system.. no real huge electrical load, no A/C.
I assume the rad fans were working when the stalling problem occured since it's pretty hot outside and I was not on the highway, and I was listening to music on the stock bose system.. no real huge electrical load, no A/C.
08-12-09, 11:04 PM
#6
It`s the "dying when hot at idle" thing that is making me wonder about it. Mine did it before I dumped the engine & put in a new one recently. Low compression & a coolant seal leak was its demise.
On the low boost issue, have you checked to see if you have the pills in the hoses on the turbocharger actuators?
Are the vacuum hoses on the engine new or are they the stock ones that were always on the motor before you bought it?
On the low boost issue, have you checked to see if you have the pills in the hoses on the turbocharger actuators?
Are the vacuum hoses on the engine new or are they the stock ones that were always on the motor before you bought it?
08-13-09, 02:29 AM
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I gotta correct what i said, I drove the car tonigh,. and the "die at idle" thing happens when I use A/C. Actually I use the automatic climate control but it's so hot outside, it just blows A/C like crazy.
When I don't use it, it idles perfectly.
the compression is good on the engine, and no coolant seal toast.
the vacuum lines job was done a year ago.
When I don't use it, it idles perfectly.
the compression is good on the engine, and no coolant seal toast.
the vacuum lines job was done a year ago.
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08-13-09, 09:03 AM
#8
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distributer cap may be cracked or broken letting water in and not supplying the correct amount of volts, this has happened on my dads merc 190e and that thing used to cut out when slowing to a stop. i presume rotaries have distributed caps, im not sure though. could be an easily sorted problem.
hope this helps
jonny
hope this helps
jonny
08-13-09, 09:19 AM
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could be distributer cap? maybe the camshaft or valves went? oh wait it's a rotary, doesn't have any of this crap. imo ppl should only try to give advise if they actually know what they are talking about.
08-13-09, 11:54 AM
#13
Might want to verify that the connector to it is still plugged in all the way.
The FSM is stating that the resistance of the unit should be 10.7 ~ 12.3 ohms @ 68 degrees. You could measure the thing & see if it is reading right & also that it hasn`t opened up. Could also measure the voltage to the connector & make sure it is active when the A/C is turned on.
Last edited by Speeder165; 08-13-09 at 12:08 PM.
08-13-09, 12:44 PM
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I had this problem (engine dying) in one of my FDs. My problem was the lighter flywheel. RPMs slowed down to fast when coming to a stop. I adjusted my driving style and it happened less frequently.
08-13-09, 01:17 PM
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Rotary Ninja
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if you had a PFC this would be alot easier to diagnose haha. but im sticking with the IACV. your idle should raise when you
1. the Electric load controller sends a signal (this happens with the A/C fans on 3 or 4, the rear defroster on, or the parking lights on)
2. when the A/C switch is on.
try and see if the idle rises when you turn the rear defroster on, this should let you know if the IACV is working like it should. also what is your idle speed with all electronics and A/C off?
1. the Electric load controller sends a signal (this happens with the A/C fans on 3 or 4, the rear defroster on, or the parking lights on)
2. when the A/C switch is on.
try and see if the idle rises when you turn the rear defroster on, this should let you know if the IACV is working like it should. also what is your idle speed with all electronics and A/C off?
08-13-09, 11:38 PM
#16
First you need to clean the ISC and try the factory idle set procedure. I have covered that in this thread: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/idle-screw-adjust-854571/
08-14-09, 11:36 AM
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no need to be a PR**k about it run people down. i am only trying to help.
08-14-09, 12:17 PM
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08-14-09, 09:51 PM
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My 1986 Mazda RX-7
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hey everyone i have a 88 turbo 2 and im having a problem sorta like this i just installed a rebuilt turbo i bought stock turbo and it ran perfect no leaks then i took it on the highway and i was in 5th gear and got on it my boost gauge read about 25 pounds and then i heard a pop when i let off and lost alllll boost when i tryed excelerating it bogged down almost like a fuel cut only pushing like 3 pounds of boost when i take it out of gear the car dies unless i toggle the trottle i can also hold the vane air flow meter open and it will run when i let it go car dies instantly please advise and give me some pointers to look for when i got to diagnose this problem... btw all charge piping and vacume lines are still connected
09-18-09, 10:14 AM
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My 1986 Mazda RX-7
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lol the cupler ripped eek all good now i got another problem lol just this past weekend after filling up with gas started ideling bad and the next day i had no power and only pushing 4 psi of boost turned idle screw up to keep running floods engine often and its just really slow on excel advise
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