new to us RHD JDM FD3S not running right
11-26-11, 09:11 AM
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new to us RHD JDM FD3S not running right
Hi all! A little background first, I have always loved the 3rd gen RX7 but never had the opportunity/means to have one... Now my younger brother finds one for a good buy from a friend, but it's not running right. That's where I come in... I run a marina, so I have good mechanical knowledge, primarily of pison engines, but definately know the principals of rotarys. I also dabbled in honda tuning going back 8 yrs ago or so, so I know the basics of forced induction etc...
so I was looking for some insight into this FD3 problem. Before he bought the car, I did a 1/2 azzed compression test and am pretty sure that the apex seals are ok, (I did not remove the schrader valve from the compression tester, as I found some info that told me that just holding the pressure releif valve on the tester would work, it did somewhat, but would not allow the gauge to give full readings, but it did seem to give even pulses, so I think the apex seals were ok) if I did not hold the pressure releif, the pressure would hit about 110 psi....
Someone has previously changed some of the vacuum lines, however it looks like they only did mainly the easy to access ones, so I do plan on replacing them all over the winter.
The problem is when driving the car, when rolling along, and you gently start rolling into the throttle, it feels like it starts to make some boost, then at probably the 4K mark it falls on it's face... with a few other hiccups and snorts mixed in... Of course, no factory boost gauge, so I am looking to beg/borrow a boost gauge from a few sources locally so that I can see exactly what the boost level is doing... any common failures which would cause the above symptoms? (once she's up and running good, it will for sure get it's own pillar mounted gauge)
The car has Apexi cone style air filters in place of the factory air box, and at some point had some kind of gauges etc mounted to the dash, which can be told by the hole in the centre dash speaker gril for wire routing and a few screw holes for their mounting... it has an aftermarket exhaust as well, but I haven't been underneath yet to see what kind and or if it has had a downpipe or not...
Thanks
Matthew
so I was looking for some insight into this FD3 problem. Before he bought the car, I did a 1/2 azzed compression test and am pretty sure that the apex seals are ok, (I did not remove the schrader valve from the compression tester, as I found some info that told me that just holding the pressure releif valve on the tester would work, it did somewhat, but would not allow the gauge to give full readings, but it did seem to give even pulses, so I think the apex seals were ok) if I did not hold the pressure releif, the pressure would hit about 110 psi....
Someone has previously changed some of the vacuum lines, however it looks like they only did mainly the easy to access ones, so I do plan on replacing them all over the winter.
The problem is when driving the car, when rolling along, and you gently start rolling into the throttle, it feels like it starts to make some boost, then at probably the 4K mark it falls on it's face... with a few other hiccups and snorts mixed in... Of course, no factory boost gauge, so I am looking to beg/borrow a boost gauge from a few sources locally so that I can see exactly what the boost level is doing... any common failures which would cause the above symptoms? (once she's up and running good, it will for sure get it's own pillar mounted gauge)
The car has Apexi cone style air filters in place of the factory air box, and at some point had some kind of gauges etc mounted to the dash, which can be told by the hole in the centre dash speaker gril for wire routing and a few screw holes for their mounting... it has an aftermarket exhaust as well, but I haven't been underneath yet to see what kind and or if it has had a downpipe or not...
Thanks
Matthew
11-27-11, 11:10 AM
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Ok, I got digging into things yesterday, and figured I'd add some more info... I read somewhere that you should see close to 4 psi if you rev the engine in neutral, so took one of my marine tools apart, a gearcase pressure tester which has a pressure gauge on it and tapped it into the boost gauge port, and started the car, I reved it from under the hood using the throttle body, but am not sure how may rpm's I hit, but prob no where near redline or wot but from having my head under the hood it seemed like some decent Revs, but the pressure gauge never even moved.... So I thought maybe an intake system leak, So I started tearing things apart for the heck of it, and tried pressurizing each piece from the turbo y pipe, thru the intercooler, till I hit the throttle body, and did not find any major signs of leakage or problems there... only issue that I found there was the vacuum line where it attaches to the air bypass valve had a small worn though spot where it had been rubbing on one of the factory clamps, I just cut that end inch off that tube and reconnected it... I did remove the air bypass valve and tested it as well and it was ok.
So no apparent source for loss in boost between the turbo y-pipe and the t-body... Currently I still have all those pieces removed, I also removed the strut tower brace and then pulled the pressure storage caniser out of the way to be able to look under the intake manifold at some of the solenoids etc.... Keep in mind the car has some silicone lines and some original, so someone has messed with this beast before... First thing I noticed was 2 silicone lines not connected to anything, just the ends hanging there, and then I noticed there is a small bracket with 2 solenoids attached to it, and it bolts to the upper intake manifold, well there were no bolts in it, so I swung the bracket/solenoids out a little, and there were no lines attached at all to the right solenoid, and the left solenoid had 2 silicone lines on it each prob 3-4 inches long, but they were not connected to anything.... As far as I can tell these 2 solenoids should be the wastegate control and turbo pre-control so they should sure as heck be connected up shouldn't they?? even if someone had done a poor man's non sequential conversion the wastegate should be hooked up, correct?? and if someone had done the non sequential conversion then the precontrol gate should be wired open as well, but it still seems to be attached to the actuator as it should be... I then thought I would check the wastegate actuator, and I could not more the linkage rod by hand, so I removed the E clip that fastens the link rod to the wastegate arm, and the wastegate arm moves, not a huge range of motion, prob 30 degrees or so? Then I thought maybe the wastegate acuator was possibly bad, stuck holding the wastegate open, so i thought while I had the link rod off, I had someone start the car and rev it some while I both held my hand over the turbo y-pipe outlet and moved the wastegate arm back and forth. what I found was it seemed to have more boost when the arm was in the same state as when I removed the link rod, telling me that the wastegate was not stuck open... I proceeded to try and test the wastegate actuator, but due to the 2 lines from it, I was trying to apply both pressure and vacuum to the 1 port with no results, but from some more research I realize now, the port that I was trying to test from should have been plugged and I should have pressurized the other port to test the wastegate.... How much airflow/pressure should I have been able to feel while holding my hand over the turbo y pipe while reving the engine under no load in neutral?? I would have assumed I would have felt more that what I did... I guess one major piece that I didn't look at yet was the charge control valve, since, correct me if I am wrong, would bleed off boost pressure from the turbo y pipe if it was not operating correctly??
Thanks for any insight guys
Matthew
So no apparent source for loss in boost between the turbo y-pipe and the t-body... Currently I still have all those pieces removed, I also removed the strut tower brace and then pulled the pressure storage caniser out of the way to be able to look under the intake manifold at some of the solenoids etc.... Keep in mind the car has some silicone lines and some original, so someone has messed with this beast before... First thing I noticed was 2 silicone lines not connected to anything, just the ends hanging there, and then I noticed there is a small bracket with 2 solenoids attached to it, and it bolts to the upper intake manifold, well there were no bolts in it, so I swung the bracket/solenoids out a little, and there were no lines attached at all to the right solenoid, and the left solenoid had 2 silicone lines on it each prob 3-4 inches long, but they were not connected to anything.... As far as I can tell these 2 solenoids should be the wastegate control and turbo pre-control so they should sure as heck be connected up shouldn't they?? even if someone had done a poor man's non sequential conversion the wastegate should be hooked up, correct?? and if someone had done the non sequential conversion then the precontrol gate should be wired open as well, but it still seems to be attached to the actuator as it should be... I then thought I would check the wastegate actuator, and I could not more the linkage rod by hand, so I removed the E clip that fastens the link rod to the wastegate arm, and the wastegate arm moves, not a huge range of motion, prob 30 degrees or so? Then I thought maybe the wastegate acuator was possibly bad, stuck holding the wastegate open, so i thought while I had the link rod off, I had someone start the car and rev it some while I both held my hand over the turbo y-pipe outlet and moved the wastegate arm back and forth. what I found was it seemed to have more boost when the arm was in the same state as when I removed the link rod, telling me that the wastegate was not stuck open... I proceeded to try and test the wastegate actuator, but due to the 2 lines from it, I was trying to apply both pressure and vacuum to the 1 port with no results, but from some more research I realize now, the port that I was trying to test from should have been plugged and I should have pressurized the other port to test the wastegate.... How much airflow/pressure should I have been able to feel while holding my hand over the turbo y pipe while reving the engine under no load in neutral?? I would have assumed I would have felt more that what I did... I guess one major piece that I didn't look at yet was the charge control valve, since, correct me if I am wrong, would bleed off boost pressure from the turbo y pipe if it was not operating correctly??
Thanks for any insight guys
Matthew
11-27-11, 08:26 PM
#3
Wow, you dumped a lot of information. I probably will not be able to answer all of your questions because of the density.
Q1: How old is the fuel in the tank? Fortunately for you being in Canada and running a marina, you have access to good ethanol-free premium octane fuel. Use that only.
Q2: Has the fuel filter ever been changed? This is located above the differential. I suggest you also run the standard fuel pressure tests as found in the FSM and if you're unsure about the filter change that. Change the fuel filter every 20k or couple of years.
Q3: Have you put in fresh spark plugs? Use the factory plugs. Rotaries kill plugs pretty regularly (every 10k).
Q4: Does/did the car rev over 4k without an issue at idle or other light loads?
As for the boost problem, it's good that you're finding and fixing loose vacuum lines and while you're in there it's your opportunity to fix everything you can. Opening the rats nest on an older FD might also be named opening Pandora's box. The wiring, injectors, fuel lines, vacuum lines, check valves, and solenoids all deserve inspection, testing, and replacement as necessary. You dove into a pretty big job that can exceed a transmission rebuild in cost and detail. Pay particular attention to the wiring harness, as the vinyl sleeving goes brittle and forms pinch points for cutting into the wiring which has also hardened. If you want to go under the UIM and "do it once", then items like solenoid testing, FPD replacement, and injector cleaning should be considered.
Since you can see that someone did a partial hose replacement, be on the lookout for things that weren't done correctly. Backwards check valves, pinched lines, broken solenoid nipples that were glued back together, incorrectly routed lines, etc.
The KOKO test for the turbo system is actually rather hard to pass, even for a car with pretty good boost pattern. It's that 4psi in neutral that my car never generates, yet I have a reasonably good 10-5-10 pattern. It's unfortunate that you don't have a boost pattern right now to help guide your troubleshooting.
At this point you could proceed pulling everything apart and try to root out every possible problem or future failure point, or you can tidy up what you found and put it back together for further road testing. I've taken both roads and there is not a wrong choice.
If you want to continue testing actuators and stuff there is a good site that covers nearly every turbo control function: http://www.autosportracetech.com/RX-7/rx7stuff.htm . The Mazda tests for the components are found in section F of the Factory service manual. https://www.rx7club.com/3rd-generation-specific-1993-2002-16/94-fsms-available-download-449950/
I've also written up my experience doing a "hose job" on my car at www.davidgeesaman.com. There are other (and probably better
) sources to consider here: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faq-3rd-gen-other-useful-links-68640/
Dave
Q1: How old is the fuel in the tank? Fortunately for you being in Canada and running a marina, you have access to good ethanol-free premium octane fuel. Use that only.
Q2: Has the fuel filter ever been changed? This is located above the differential. I suggest you also run the standard fuel pressure tests as found in the FSM and if you're unsure about the filter change that. Change the fuel filter every 20k or couple of years.
Q3: Have you put in fresh spark plugs? Use the factory plugs. Rotaries kill plugs pretty regularly (every 10k).
Q4: Does/did the car rev over 4k without an issue at idle or other light loads?
As for the boost problem, it's good that you're finding and fixing loose vacuum lines and while you're in there it's your opportunity to fix everything you can. Opening the rats nest on an older FD might also be named opening Pandora's box. The wiring, injectors, fuel lines, vacuum lines, check valves, and solenoids all deserve inspection, testing, and replacement as necessary. You dove into a pretty big job that can exceed a transmission rebuild in cost and detail. Pay particular attention to the wiring harness, as the vinyl sleeving goes brittle and forms pinch points for cutting into the wiring which has also hardened. If you want to go under the UIM and "do it once", then items like solenoid testing, FPD replacement, and injector cleaning should be considered.
Since you can see that someone did a partial hose replacement, be on the lookout for things that weren't done correctly. Backwards check valves, pinched lines, broken solenoid nipples that were glued back together, incorrectly routed lines, etc.
The KOKO test for the turbo system is actually rather hard to pass, even for a car with pretty good boost pattern. It's that 4psi in neutral that my car never generates, yet I have a reasonably good 10-5-10 pattern. It's unfortunate that you don't have a boost pattern right now to help guide your troubleshooting.
At this point you could proceed pulling everything apart and try to root out every possible problem or future failure point, or you can tidy up what you found and put it back together for further road testing. I've taken both roads and there is not a wrong choice.
If you want to continue testing actuators and stuff there is a good site that covers nearly every turbo control function: http://www.autosportracetech.com/RX-7/rx7stuff.htm . The Mazda tests for the components are found in section F of the Factory service manual. https://www.rx7club.com/3rd-generation-specific-1993-2002-16/94-fsms-available-download-449950/
I've also written up my experience doing a "hose job" on my car at www.davidgeesaman.com. There are other (and probably better
) sources to consider here: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faq-3rd-gen-other-useful-links-68640/Dave
11-28-11, 11:19 AM
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David, Thank you for your help, I printed out all your turbo and vacuum related pages... I have seen the hose diagrams before, but I think yours is the most colourful and easiest to differentiate between the plethora of hoses in the rats nest! I was planning on replacing all of the vacuum hoses over the winter, I just wanted to try and make some boost and do a pass or 2 across the parking lot here at the marina before the snow hits, but considering I have all the intake piping and intercooler out from the turbo y pipe to the t-body, I probably should just tear off the upper intake manifold and keep diggin'!!
Thanks again
Matthew
Thanks again
Matthew
