Difficulty starting, rough idle, loss of power

[jsilva]

I recently bought a Speed6 which I’m working up and am unsure about a problem I’m currently troubleshooting.

Symptoms:

- When cold it will stall a second after starting. I have to rev the engine up to around 2500 rpms for 30 seconds so that it won’t stall.

- Before it warms up it has some significant hesitations/bucking when driving.

- When it’s warmed up it has a rough idle. Almost feels like it wants to stall but doesn’t. Hovers around 650-700 rpms.

- It has a loss of power.

I should say that this issue started after I replaced the fuel injectors (the injectors were new). At first I thought it was because of a fuel leak at the pressure sensor and a loss of fuel pressure—the fuel rail threads for the sensor were actually stripped and so I replaced the fuel rail along with the seals on the injectors and fuel rail. Leak stopped but problem persisted.

So I started wondering what else I did when I replaced the injectors and I assumed it was a vacuum leak, and it may be, but I haven’t been able to find it (though my only way to test is to spray around with carb cleaner while engine is cold). I did end up replacing the MAP sensor as well.

The only other thing that I did was I accidentally pulled the oil dipstick holder out of the engine/oil pan. It must have already been loose since it came out easily. I tried to get it back in but it’s possible I wasn’t able to get it back perfectly.

So then I wondered if an air leak around the dipstick holder might affect the pressure in the crankcase and cause the symptoms I’m experiencing?

Any advice would be greatly appreciated! Thanks.

 

[Solarsurge]

Since the intake manifold has to be removed to replace the injectors, I would begin my search there. If you’re using the stock IM, there is a spacer on the backside of the bottom right of the manifold that the bolt goes through. It is VERY easy to lose if you’re not specifically looking for it and that makes the top of the manifold sit flush on the head. If that bolt was tightened down first, the entire manifold may not be sealed to the head right. Other than that, a vacuum or PCV hose may be loose/disconnected.


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[VashEXE]

A log would really help troubleshoot this. Intake manifold leaking sounds very plausible. You'd see it very easily in a logs. Make sure you're logging STFT, LTFT, and AFRs.

 

[jsilva]

Thanks solarsurge. I’ll have to check about the spacer ... I didn’t know it was there.

What do you think about reusing the intake manifold gasket? I had replaced it in early Jan and didn’t want to replace it again. Perhaps that could be the issue?

Interestingly, the gasket on the car when I got it was 3-4mm white plastic. Not sure if it was custom made or purchased from a parts maker. I replaced it with the Mazda metal gasket. Do you think the plastic would be as good or better?

 

[VashEXE]

Thanks solarsurge. I’ll have to check about the spacer ... I didn’t know it was there.

What do you think about reusing the intake manifold gasket? I had replaced it in early Jan and didn’t want to replace it again. Perhaps that could be the issue?

Interestingly, the gasket on the car when I got it was 3-4mm white plastic. Not sure if it was custom made or purchased from a parts maker. I replaced it with the Mazda metal gasket. Do you think the plastic would be as good or better?

That's an AP TIG gasket probably. Better than OEM. I think they say you shouldn't reuse it, but I've seen others reuse it and as long as it looks fine you're probably alright. You should really get a log though, you'll be able to see if you have a big leak real quick rather than just messing around with a bunch of stuff. You can also just hook up a boost leak tester and that'll answer that question for you real quick.

 

[jsilva]

Thanks VashEVE.

Are you referring to reusing the AP TIG gasket or the metal Mazda one? I’ve known it’s questionable to reuse the metal gaskets, but it did look pretty much the same as new which is why I reused it. The white plastic one looks fine too—should I switch back to that? (Photo below)

I have the ODB Fusion app although I’ve not done any logging before. I’ve done car repairs for a while but I’m venturing into new territory with this Speed6 I’ll see about logging the STFT, LTFT, and AFRs. What am I looking for in terms of a leak?

 

[VashEXE]

Thanks VashEVE.

Are you referring to reusing the AP TIG gasket or the metal Mazda one? I’ve known it’s questionable to reuse the metal gaskets, but it did look pretty much the same as new which is why I reused it. The white plastic one looks fine too—should I switch back to that? (Photo below)

I have the ODB Fusion app although I’ve not done any logging before. I’ve done car repairs for a while but I’m venturing into new territory with this Speed6 I’ll see about logging the STFT, LTFT, and AFRs. What am I looking for in terms of a leak?


View attachment 13623

That gasket is the AP one. This looks fine and I wouldn't think there would be any problems with that. One of the first things you buy should be an accessport. It helps your troubleshooting ability quite a bit and a decent tune will make it a completely different car.

Make sure the car isn't coldstarting and let it idle if it can. What I mean is, do this while the car is warmed up. When it's coldstarting STFT and stuff will be all over the place for a bit. If you have a crazy leak you're going to see STFT go really positive or negative. LTFT is just an average of STFT over time at certain loads/rpms and AFR is what that's directly affecting. At idle you're hoping for 14.85AFR all the time and STFT/LTFT as close to 0 as possible, but that'll move around a little bit no matter how good your tune is.

 

[jsilva]

Thanks VashEXE. I think I’ll go ahead and put back in this AP gasket so at least I won’t have to worry that it’s the metal OEM gasket being reused.

I will check out the fuel trim after that, I’ve already setup ODB Fusion.

I’d really like to work the car up nicely, possibly even rebuild the motor. But that’ll have to wait until the summer. Right now I just want it to run reasonably well. The last thing after this is to determine where a transmission leak is coming from—I think it’s the passenger side axle seal, but I’m not totally certain.

 

[Solarsurge]

Thanks VashEXE. I think I’ll go ahead and put back in this AP gasket so at least I won’t have to worry that it’s the metal OEM gasket being reused.

I will check out the fuel trim after that, I’ve already setup ODB Fusion.

I’d really like to work the car up nicely, possibly even rebuild the motor. But that’ll have to wait until the summer. Right now I just want it to run reasonably well. The last thing after this is to determine where a transmission leak is coming from—I think it’s the passenger side axle seal, but I’m not totally certain.

Leaking passenger side axle seal is incredibly common for anyone who has ever done an engine swap or clutch replacement. Those seals tend to get hard and brittle over time with heat exposure, which is 100% of the time in a transmission, so all it takes is for the axle to bump it when you’re pulling it out for it to crack. And since 90% of the time people NEVER plan for that and order replacement seals, they just put it back together again and send it.


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[jsilva]

Thanks solarsurge. As I understand it, this Speed6 actually had an engine swap last year.

 

[jsilva]

Ok...

I changed the intake manifold gasket to the AP one. Car started better and in some ways it runs better but overall it’s still having the same issues. Besides the hesitations and stalling when it’s not warmed up (which are better), it feels like it has no boost even when it is warmed up. There is a DC Sport air intake which is annoyingly noisy, so I know the turbo is working

However, I noticed an issue with the nut that screws the EGR into the intake manifold. I don’t think it’s able to screw in tight enough.

Could the EGR pipe not being properly secured cause the issues I’m having?

If you’re interested, here are some photos from ODB Fusion.

This was taken when the temperature gauge went to the halfway mark and it was idling:


Then suddenly it did this:


This is how it idled after that:


This was when I accelerated more aggressively:

 

[VashEXE]

Ok...

I changed the intake manifold gasket to the AP one. Car started better and in some ways it runs better but overall it’s still having the same issues. Besides the hesitations and stalling when it’s not warmed up (which are better), it feels like it has no boost even when it is warmed up. There is a DC Sport air intake which is annoyingly noisy, so I know the turbo is working

However, I noticed an issue with the nut that screws the EGR into the intake manifold. I don’t think it’s able to screw in tight enough.

Could the EGR pipe not being properly secured cause the issues I’m having?

If you’re interested, here are some photos from ODB Fusion.

This was taken when the temperature gauge went to the halfway mark and it was idling:
View attachment 13625

Then suddenly it did this:
View attachment 13626

This is how it idled after that:
View attachment 13627

This was when I accelerated more aggressively:
View attachment 13628

These graphs are really hard to read and are completely useless. Can you get a text output or something like a normal accessport log? You don't need to log your MAF stuff for now. If your EGR pipe is loose or having issues this could definitely cause problems since it goes right into the intake manifold and you'd have a really bad boost leak.

For shits and giggles, try just removing the bolt on the bottom of the intake manifold that bolts in near the starter. Here's the one I mean:


I had issues with this support causing the manifold not to mate up properly with the head and I know many others have as well. That's a good first step. Another thing you need to do is a boost leak test. Go out and build you own if you need to, it's not expensive and will save you a lot of time in troubleshooting.

I'm going to say it again, even though you have this goofy OBD app, an accessport will let you flash tunes and actually take advantage of your car. You should really consider getting one used even. It'll let you take logs in a way that everybody here is used to working with.

 

[jsilva]

Thanks VashEXE.

I can output the log in a CSV text file although I thought the graph was easier to see at a glance. But ... you certainly know more about what you’re looking for than I do! It’d probably be easier to follow if I only had one fuel trim and air fuel only.

I’d like an accessport (what do you think of VersaTuner?), but with the unknown of this car it’s a little hard to justify spending the money when I may end up needing to buy a new motor (there are other unrelated issues I haven’t mentioned).

My concern over the EGR pipe is that it seems like the threads in the intake manifold are somewhat damaged. The nut goes in off centre and is difficult to tighten. I’m not sure why I didn’t notice previously, or maybe it’s just gotten worse. I tried for maybe 15 minutes to get the nut to go in straight but it refused, so I just tightened it to the point where it seemed wrong to keep going. That may have been a mistake, but either way I may need to get a replacement intake manifold.

Maybe I could do an EGR delete but I need it to pass inspection in Sept

 

[Solarsurge]

What injectors and seals did you use when you replaced your injectors? OEM?


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[VashEXE]

Thanks VashEXE.

I can output the log in a CSV text file although I thought the graph was easier to see at a glance. But ... you certainly know more about what you’re looking for than I do! It’d probably be easier to follow if I only had one fuel trim and air fuel only.

I’d like an accessport (what do you think of VersaTuner?), but with the unknown of this car it’s a little hard to justify spending the money when I may end up needing to buy a new motor (there are other unrelated issues I haven’t mentioned).

My concern over the EGR pipe is that it seems like the threads in the intake manifold are somewhat damaged. The nut goes in off centre and is difficult to tighten. I’m not sure why I didn’t notice previously, or maybe it’s just gotten worse. I tried for maybe 15 minutes to get the nut to go in straight but it refused, so I just tightened it to the point where it seemed wrong to keep going. That may have been a mistake, but either way I may need to get a replacement intake manifold.

Maybe I could do an EGR delete but I need it to pass inspection in Sept

If you had an Accessport you could disable that code in your tune and pass anyways .

If you decide to build your motor, you really will need an accessport to get your tune correct and check CELs and stuff. Any money on an Accessport could be easily made back by selling it for what you paid for it, you just have to unmarry it from your car. Just think about it, it'll make things so much easier for you.

You can also just get a helicoil and repair the threads for the EGR pipe as well. A boost leak test would tell you if it was leaking there though, so if you don't want to spend much money and don't want to do any of the other stuff, at least do a boost leak test.

 

[jsilva]

Solarsurge, I used new OEM injectors (as far as I know...they could be eBay fakes) and they came with seals except the front seal. When I replaced the fuel rail I replaced all of the seals with GB remanufacturing (yes I installed the front seal in the correct direction).

I’m sure you’re right VashEXE and I’ll definitely consider it. Do you have a preferred cheap boost leak tester? I had been considering taking it to a garage and pay them to diagnose a leak, but obviously I can’t do that right now.

 

[jsilva]

I found an intake manifold locally with an EGR pipe/nut for not too much so I’ll get that. I’ll report back once either install it or do a boost leak test.

 

[jsilva]

I installed the intake manifold today... It’s definitely a lot faster, so something was fixed. There feels like a lot more power.

However, it still had trouble starting and had some hesitations when cold (though hesitations were significantly better). The idle was still rough but it didn’t feel like it was going to stall.

A couple of things I didn’t say before:

1. The engine would tend to get really hot. To the extent that I’d be concerned. It’d actually cool down when I’d drive fast and get the RPMs up. I thought it was fixed today because it was staying at 190° while I was test driving, but when I got back I idled and it went up to 214° before I turned it off.

2. The turbo is spewing oil. Enough that every time I take off the intercooler I see oil, even after only one drive. And the times I’ve taken off the intake manifold it’s dripping off the gasket. And that’s fouling up the spark plugs as well. I do have a new turbo arriving tomorrow but I’m not sure when I’ll have time to put it in.

So does any of this new information give a clue as to what’s going on?

 

[Enki]

More likely blowby and PCV issues than turbo issues. Check the inlet of the turbo to see if there's oil pooling in front of the compressor; if there is, it's probably from PCV stuff.

Also, just check out the MAF housing and general intake, specifically any airflow straighteners.

 

[jsilva]

Thanks Enki. I haven’t looked at the turbo, but there is oil in the air intake (I have a DC Sports overly noisy intake) from where the hose from the valve cover attaches—when I’ve disconnected the air intake I can see oil in the pipes.

However, there isn’t any pooling of oil in the intake manifold. Does that matter? Does fixing PCV issues on this car entail just replacing the PCV valve or are there other issues to address?