Jump to content
The mkiv Supra Owners Club

Fuelling Issues


Big Supes

Recommended Posts

The old girls seems to have developed some feeling issues recently that I'm looking into. 

Its a bit annoying as I'm swapping the entire fuel system out later in the year, but for now I'd like to diagnose the problem.

The car has a very faint misfire. It runs rich in idle (but kinda always has tbh), but feels like it might be suffering from low pressure at high rpm. 

When a friend followed me the other day he said the car had an eggy smell to it. I also smelt it, but thought it was another car. I haven't driven it since. 

To start diagnosing, I've got a new fuel filter to replace so while I'm there, I'll test the fuel pressure. If that checks out ok, I guess its time to replace the FPR. 

BTW, I've checked the injector resistor pack and it checks out ok. 

Is there anything else I'm missing?

Link to comment
Share on other sites

14 hours ago, Big Supes said:

The old girls seems to have developed some feeling issues recently that I'm looking into. 

Its a bit annoying as I'm swapping the entire fuel system out later in the year, but for now I'd like to diagnose the problem.

The car has a very faint misfire. It runs rich in idle (but kinda always has tbh), but feels like it might be suffering from low pressure at high rpm. 

When a friend followed me the other day he said the car had an eggy smell to it. I also smelt it, but thought it was another car. I haven't driven it since. 

To start diagnosing, I've got a new fuel filter to replace so while I'm there, I'll test the fuel pressure. If that checks out ok, I guess its time to replace the FPR. 

BTW, I've checked the injector resistor pack and it checks out ok. 

Is there anything else I'm missing?

Rotten egg smell (Sulphur Dioxide) is a by product of fuel getting to the catalytic converter, so ties in with the over fuelling.

Link to comment
Share on other sites

7 hours ago, Tyson said:

I guess any surface getting hot enough can undergo the same chemical reaction? I am not a chemist so I have no idea 😃

That's generally what I thought as well. 

I failed miserably at chemistry, but have made some wicked party fruit punches in my time. 🤪🤯😂

  • Like 1
Link to comment
Share on other sites

Checked the continuity on the fuel pump, bypassed the fuel pump ecu so it's on a constant 12v and changed the fuel filter.... not 100% convinced it's sorted. Pulled hard in 2nd gear, but still feels like it's missing slightly when you get into 3rd on WOT. 

Will check the fuel pressure once I've got a pipe with banjo (plus banjo bolt) to put onto my tester. 

TBH, I've had confirmation that my turbo and manifold are in the post so I'm tempted to start pulling the twins off Monday and sort this fuelling issue with the Link ECU. 

Will do a compression test merely out of interest before going single. 

Link to comment
Share on other sites

Map Sensor/fuel pressure regulator hoses vaccum hose leaks can cause fuelling issues. I also had my map sensor melt on the underneath..

Check the vac hoses to the VSV's as well. My IACV VSV had a loose fitting hose, replacing that leaned my fuelling out from the 9.0s on WOT to 10s..

Vac hoses leaking are the cause of many issues, I replaced the whole lot.

The link pipes on the turbos collapse on the inside, restricting boost, causing AFR's to get rich.. 

I had fixed all of these before tuning the car on the Link, made a huge difference even before tuning..

Edited by Samurai 20V (see edit history)
Link to comment
Share on other sites

On 3/6/2022 at 6:00 PM, Samurai 20V said:

Map Sensor/fuel pressure regulator hoses vaccum hose leaks can cause fuelling issues. I also had my map sensor melt on the underneath..

Check the vac hoses to the VSV's as well. My IACV VSV had a loose fitting hose, replacing that leaned my fuelling out from the 9.0s on WOT to 10s..

Vac hoses leaking are the cause of many issues, I replaced the whole lot.

The link pipes on the turbos collapse on the inside, restricting boost, causing AFR's to get rich.. 

I had fixed all of these before tuning the car on the Link, made a huge difference even before tuning..

Thanks mate, I've started pulling the twins off now so it'll be off the road for a bit. The next time it starts it should be on a Link ecu so will hopefully get a better idea as to what's going on.

Link to comment
Share on other sites

On 3/7/2022 at 11:40 PM, Big Supes said:

Thanks mate, I've started pulling the twins off now so it'll be off the road for a bit. The next time it starts it should be on a Link ecu so will hopefully get a better idea as to what's going on.

Good luck mate.. I'm heading for the same job soon, 6266 PHR kit going on soon..

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.