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Trouble getting the car started after rebuild

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Old 03-14-20 | 02:51 PM
  #126  
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Idk if my eyes are playing tricks on me or something. But is your car right hand drive? And is your ABS pump brake line plumbing different than mine?

The only ground I see in that area is a very short one from the chassis to the ABS pump itself. But my wire is black with yellow stripe. Not red.
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Old 03-14-20 | 03:05 PM
  #127  
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From: Trois-Rivieres (QC)
Originally Posted by TwinCharged RX7
Idk if my eyes are playing tricks on me or something. But is your car right hand drive? And is your ABS pump brake line plumbing different than mine?

The only ground I see in that area is a very short one from the chassis to the ABS pump itself. But my wire is black with yellow stripe. Not red.
Yes, car is right-hand drive. 1st wire that I have shown is black with yellow stripe. 2nd wire is black with red stripe. Black with yellow stripe: I'm assuming it goes to the top bolt of the starter. Black with red stripe: I've got no clue where it goes...
Old 03-14-20 | 03:38 PM
  #128  
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Black with red stripe on your car is a black with yellow stripe on mine. It goes chassis ground to ABS module. It's only like 6-12 inches long if it's like my LHD version.

Either that or it's a completely different wire and I don't know where that would go.
Old 03-14-20 | 04:05 PM
  #129  
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From: Trois-Rivieres (QC)
Originally Posted by TwinCharged RX7
Black with red stripe on your car is a black with yellow stripe on mine. It goes chassis ground to ABS module. It's only like 6-12 inches long if it's like my LHD version.

Either that or it's a completely different wire and I don't know where that would go.
If I recall correctly, I had to remove it when I took it out from the car (and I don't think it was there). At this point I'm pretty sure I could just sand the chassis where it's bolted and I would be good, but I'd like to put it in the right place of course...
Old 03-14-20 | 04:09 PM
  #130  
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Yeah. That should work. But I don't think that is your problem. The ground near the starter could be one of the main issues as that's the biggest engine to chassis ground.
Old 03-14-20 | 05:21 PM
  #131  
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From: Trois-Rivieres (QC)
Originally Posted by TwinCharged RX7
Yeah. That should work. But I don't think that is your problem. The ground near the starter could be one of the main issues as that's the biggest engine to chassis ground.
Let's forget about that black wire with red stripe, it seems that it's been bolted there forever, I think it goes with the ABS module.

But now... That black wire with yellow stripe.

I tightened that bolt. That's all I did. I'm now getting a peak cranking speed of 210 RPM, instead of 185 RPM. It makes a massive difference to my ears. However, engine now seems to be flooded with transmission oil (I was mad when I saw compression numbers last night so I poured probably too much oil in there). Spark plugs are flooded with red oil. I'll have to unflood the engine a couple of time before trying again with a freshly charged battery.

I really feel that this nightmare is coming to an end.

Last edited by MuRCieLaGo; 03-14-20 at 05:24 PM.
Old 03-14-20 | 08:36 PM
  #132  
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From: Trois-Rivieres (QC)
As expected, I managed to start the car twice tonight. First time 5 seconds, 2nd time about 75 seconds.

I had 2 problems here: 1st was a loose ground on the starting circuit, 2nd was a low compression.

It runs pretty strange now. I have to keep my foot on gas pedal, otherwise it stalls.

Everytime it stops, compression becomes low, so I have to pour transmission oil one more time.

Turbo isn't connected, few nipples aren't connected on UIM, LIM to UIM isn't bolted... There are vacuum leaks everywhere. Could it be the reason why? I just screwed the small bolt in front of the throttle body that adjusts the idle.

And... To your experienced ears... Does it sound like it's running on one rotor? Remember, there are vacuum leaks all over the place right now and this is the first time the car really started after lots of months trying and trying. Engine has also been "street ported" by a rotary shop.


Last edited by MuRCieLaGo; 03-14-20 at 08:39 PM.
Old 03-14-20 | 08:40 PM
  #133  
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Fix your vacuum leaks before doing anything. That will mess up your idle and cause it to hunt and/or stall.

Have you checked compression with a tester? If it's below 80, don't bother putting anything else back together and get a rebuild.
Old 03-14-20 | 11:34 PM
  #134  
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The 30psi +\- he’s getting now is very low, but it hasn’t been ran since his rebuild at all til now, isn’t there a probability it will build decent compression? Not perfect but maybe 90 or so? It is literally brand new, I say bolt that MF all back together correct with zero vacuum leaks and let it idle for a long time for now atleast and see what happens? Engine is already installed and mainly back together what’s it gunna hurt to see before pulling it all back apart
Old 03-14-20 | 11:38 PM
  #135  
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No. 30psi doesn't just build back to 90.

I highly doubt the engine is any good.
Old 03-15-20 | 02:56 AM
  #136  
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I agree with Tyler. Skip the "what if". Reaseemble it and run it. Just expect compression to not get any better. After all this, just put it all back together...
Old 03-15-20 | 03:39 PM
  #137  
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From: Trois-Rivieres (QC)
Originally Posted by TwinCharged RX7
Fix your vacuum leaks before doing anything. That will mess up your idle and cause it to hunt and/or stall.

Have you checked compression with a tester? If it's below 80, don't bother putting anything else back together and get a rebuild.
I quickly fixed vacuum leaks. I'm closely monitor compression now...

Originally Posted by Bimmer_Tyler
The 30psi +\- he’s getting now is very low, but it hasn’t been ran since his rebuild at all til now, isn’t there a probability it will build decent compression? Not perfect but maybe 90 or so? It is literally brand new, I say bolt that MF all back together correct with zero vacuum leaks and let it idle for a long time for now atleast and see what happens? Engine is already installed and mainly back together what’s it gunna hurt to see before pulling it all back apart
Well, engine is already installed yes and no... I want to change my (single) turbo and I've got a leak somewhere at the rear end of the engine (rear main seal I suppose) so I will have to take it out no matter what... I'm not scared of opening the engine again, but I don't want to waste my time either!

Next time the engine starts I'll keep it on for 3 minutes, that's my next goal. Because right now, as soon as I let it die, I'm done for the day. It won't restart again.

Originally Posted by cr-rex
I agree with Tyler. Skip the "what if". Reaseemble it and run it. Just expect compression to not get any better. After all this, just put it all back together...
I've got to take the engine out to fix an oil leak at (most likely) the rear main seal and I want to make sure the engine is good before doing that...

Look at that black stuff spilling just under the gauge... Probably not super good for reading the compression.

Looking at the video, I'm getting a peak of 90 PSI @ 212 RPM. Engine is cold (unfortunately) and has been flooded multiple times. However, I did put some transmission oil in leading hole before.


Old 03-15-20 | 03:44 PM
  #138  
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Boy that's ALL the smoke in the video.

First off, I'm glad you found the main problem. I had a feeling it was going to be something like that. Congrats for sticking with it!

I would get your vacuum leaks taken care of and see if you can get the car to run and idle. You'll have all sorts of weird problems with vacuum leaks on the LIM side of the engine. Get that all buttoned up.

The compression is really hard to get a feel on at this point. Freshly rebuilt engines just don't have great compression at first, and one that's been cranked on, hosed down with gas, etc. just isn't going to seal that well initially. Try and get it to hold an idle and let it fully come up to temperature.

Also in the video it didn't look like your oil pressure gauge was reading. I'm hoping you just don't have the sender hooked up, if you have zero oil pressure you need to verify that first before going further.

Dale
Old 03-16-20 | 01:19 AM
  #139  
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From: Trois-Rivieres (QC)
Originally Posted by DaleClark
Boy that's ALL the smoke in the video.

First off, I'm glad you found the main problem. I had a feeling it was going to be something like that. Congrats for sticking with it!

I would get your vacuum leaks taken care of and see if you can get the car to run and idle. You'll have all sorts of weird problems with vacuum leaks on the LIM side of the engine. Get that all buttoned up.

The compression is really hard to get a feel on at this point. Freshly rebuilt engines just don't have great compression at first, and one that's been cranked on, hosed down with gas, etc. just isn't going to seal that well initially. Try and get it to hold an idle and let it fully come up to temperature.

Also in the video it didn't look like your oil pressure gauge was reading. I'm hoping you just don't have the sender hooked up, if you have zero oil pressure you need to verify that first before going further.

Dale
Thank you Dale, I appreciate your kind words and your useful posts. For the compression, that is exactly what I was thinking too. I know that the bounces are even and that's the main thing for now.

Oil pressure is unplugged, but you are right I should make sure I've got some pressure there...

However I will probably start taking the engine out tomorrow and restart from scratch. I've got to fix an oil leak that I suspect is from the rear main seal.

But before removing the engine, my final concern is...

When I remove both leading spark plugs, I can hear the compressed air beautifully. But instead, when I remove both trailing plugs, sound is very different (and I don't really like it).

Compression numbers seem to be all the same though, whether I use the leading or trailing hole.


Last edited by MuRCieLaGo; 03-16-20 at 01:13 PM.
Old 03-16-20 | 11:59 AM
  #140  
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Guys. That's not how to test compression with a piston tester.

When you hold open the bleeder valve with a zip tie like that, the needle sweeps can only be used to tell if the rotor chambers are producing equal amounts of compression.

To get actual compression with a piston tester you need to:

1. keep the bleed valve closed
2. keep the schrader valve installed in the tester threaded end

This is because:

a. the bleeder valve will bleed off pressure, but is good for showing even sweeps
b. more importantly if you take the schrader valve out you are adding the flexible hose to the combustion chamber volume and skewing your compression ratio

Get your even chamber sweeps with the bleeder pressed in. Get your max pressure with the hose end schrader valve installed and the bleeder closed. Do both rotors.
Old 03-16-20 | 01:13 PM
  #141  
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Originally Posted by alexdimen
Guys. That's not how to test compression with a piston tester.

When you hold open the bleeder valve with a zip tie like that, the needle sweeps can only be used to tell if the rotor chambers are producing equal amounts of compression.

To get actual compression with a piston tester you need to:

1. keep the bleed valve closed
2. keep the schrader valve installed in the tester threaded end

This is because:

a. the bleeder valve will bleed off pressure, but is good for showing even sweeps
b. more importantly if you take the schrader valve out you are adding the flexible hose to the combustion chamber volume and skewing your compression ratio

Get your even chamber sweeps with the bleeder pressed in. Get your max pressure with the hose end schrader valve installed and the bleeder closed. Do both rotors.
I never removed the schrader valve. Max pressure was taken with the schrader valve installed and with the bleeder valve closed (zip tie isn't installed in the following picture).

Why is the sound clearly different when leading holes are opened compared to trailing holes opened?


Last edited by MuRCieLaGo; 03-16-20 at 02:37 PM.
Old 03-16-20 | 02:30 PM
  #142  
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Originally Posted by cr-rex
thats your flasher relay causing that. the f100 relay under the dash. if you unplug it, youll find that all those problems go away. my car does exactly what you showed but it only happens when its cold. once the cabin heats up, all those problems go away. the f100 relay doesnt have anything to do with the car not starting though.
I just unplugged the F100 box and yes, the buzzer stops, and that pulsing power too... ...but the power windows don't work either.

Hopefully I can just buy another F100 box (or fix mine) and the problem will go away...
Old 03-16-20 | 08:07 PM
  #143  
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Yes, they all run through the flasher relay. So when you unplug it everything stops working. Try letting the relay sit in the sun or something to heat it up and put it back in. Like I said, mine is temperature dependant. I can put it in the freezer and install it and it will do all that weird stuff. Once it warms up, it stops.
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Old 03-17-20 | 07:27 AM
  #144  
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Originally Posted by MuRCieLaGo
I never removed the schrader valve. Max pressure was taken with the schrader valve installed and with the bleeder valve closed (zip tie isn't installed in the following picture).

Why is the sound clearly different when leading holes are opened compared to trailing holes opened?

I see. The video of the sweeps and the one picture of the max was throwing me off. Another member was saying 30 psi was low so I was clarifying that the sweeps don't show full compression.

Did you test front and rear the same way?

The sound is different leading to trailing because the leading plug hole is larger.
Old 03-17-20 | 07:01 PM
  #145  
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Originally Posted by alexdimen
I see. The video of the sweeps and the one picture of the max was throwing me off. Another member was saying 30 psi was low so I was clarifying that the sweeps don't show full compression.

Did you test front and rear the same way?

The sound is different leading to trailing because the leading plug hole is larger.
I tested front and rear exactly the same way. (The sound is very different though)...

I just started the car and it stopped after a minute or so, even if I tried to open the throttle some more (it really can't keep the idle and I fixed all vacuum "leaks").

Car is being boosted by another car. Right after the engine stopped, I couldn't restart it, cranking speed goes up to 130 RPM maximum. Voltage seems OK in my opinion.

Same thing happened last night (before I fixed vacuum leaks).

I'm going to Walmart right now to see if that battery is still good (even if it shouldn't really matter because it is being boosted).

Old 03-17-20 | 07:04 PM
  #146  
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I would see if someone will let you borrow a rotary compression tester and get a solid understanding of compression, hopefully you can rule it out as being a problem. The fact that it at least starts makes me think it's not terrible and wouldn't prevent it from continuing to run and idle. Meaning the problem is something else. But you could have a mix of issues including compression, so understanding what it is could help further trouble shooting.
Old 03-17-20 | 07:20 PM
  #147  
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You put this block together yourself from good used parts right? How were your tolerances? How'd the end play look?
Old 03-17-20 | 08:20 PM
  #148  
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Originally Posted by cr-rex
Yes, they all run through the flasher relay. So when you unplug it everything stops working. Try letting the relay sit in the sun or something to heat it up and put it back in. Like I said, mine is temperature dependant. I can put it in the freezer and install it and it will do all that weird stuff. Once it warms up, it stops.
Strange! I'll try to open it and see if everything seems OK... Right now I just unplugged it so I don't hear that buzzer anymore.

Originally Posted by TwinCharged RX7
I would see if someone will let you borrow a rotary compression tester and get a solid understanding of compression, hopefully you can rule it out as being a problem. The fact that it at least starts makes me think it's not terrible and wouldn't prevent it from continuing to run and idle. Meaning the problem is something else. But you could have a mix of issues including compression, so understanding what it is could help further trouble shooting.
I think compression doesn't mean much with such a flooded engine (it's been flooded at least 50 times in the last year). I would say the problem is something else now.

Originally Posted by Narfle
You put this block together yourself from good used parts right? How were your tolerances? How'd the end play look?
I put this block together by myself, Reknown rotary shop in Montreal surfaced the housing (and more), but I rebuilt it all by myself. I bought LOTS of tools to measure tolerances (they weren't cheap). I took my time doing this while watching 4 different DVDs. I'll figure out pretty quick if the block is good or not. Worst case I'll reopen it (or send it somewhere if I lose my golden patience).

So for the actual problem, I went to Walmart and they confirmed (again) that the battery is good... Strange.
Old 03-18-20 | 09:59 AM
  #149  
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Wait, front and rear rotors sound different or the leading and trailing sound different?

What is your battery voltage without the other car boosting it? Have you charged the current battery?

Sometimes I've seen batteries lose a cell or dead cause issues even when jumped.

That crank speed seems REALLY slow for a good battery being boosted by a running car.

I drove the FD to work today - I'll check what my cranking voltage is when i start it next. 8-9V seems low, but I've never looked.
Old 03-18-20 | 11:47 AM
  #150  
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Originally Posted by alexdimen
Wait, front and rear rotors sound different or the leading and trailing sound different?

What is your battery voltage without the other car boosting it? Have you charged the current battery?

Sometimes I've seen batteries lose a cell or dead cause issues even when jumped.

That crank speed seems REALLY slow for a good battery being boosted by a running car.

I drove the FD to work today - I'll check what my cranking voltage is when i start it next. 8-9V seems low, but I've never looked.
Leadings and trailings sound different, very different. Compression doesn't sound the same at all. Battery voltage just after I took the video was 12.88V, confirmed by Walmart. I just tried again this morning with a fully charged battery (and being boosted by another running car) and I got 160 RPM, which is still very slow.


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