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-   -   Help isolate fuel problem (https://www.miataturbo.net/ecus-tuning-54/help-isolate-fuel-problem-77761/)

Reverant 04-25-2014 01:32 PM

Or even better, a log that shows whacky TPS readings.

hustler 05-07-2014 08:56 PM

So, as of just now I have red blinky lights in sequence on the injectors, the injectors went to the flow bench and checked out, I have spark with the plugs out of the cylinder, but the car is still running on #1 and #4, I can unplug the center coil and it runs the same way. WTF is going on?

hustler 05-08-2014 11:01 PM

Is there some way I could swap the coil firing order in the computer, then swap the wires, and see if the car will then run on #2 and 3?

Reverant 05-09-2014 02:17 AM

Stock coils or toyota coils?

hustler 05-09-2014 10:41 AM


Originally Posted by Reverant (Post 1129649)
Stock coils or toyota coils?

Stock 2001 coils. I haven't jacked with the TPS yes, but I plan to in the next few days so I can get this car to COTA next weekend.

Reverant 05-09-2014 11:08 AM

If you have a spare set of plug wires from the white 1.8, the plugs will actually fit in the 2001 COPs, meaning you car rearrange the spark outputs if you get a little creative.

hustler 05-09-2014 03:31 PM


Originally Posted by Reverant (Post 1129723)
If you have a spare set of plug wires from the white 1.8, the plugs will actually fit in the 2001 COPs, meaning you car rearrange the spark outputs if you get a little creative.

I'll try that tomorrow. Thanks.

hustler 05-17-2014 05:48 PM

Tests and results I did today:
Injectors:
Noid light blinks sequentially for all four, same brightness in test mode and when cranking with the fuel pump off
All four injectors make clicky noise in test mode (injectors all flowed properly when tested a few weeks ago)

Coil tests:
All four make spark outside the engine when cranking
Coil A&b both have 12v, ground, and 1v of trigger when cranking and in test mode.
Swap coils and cylinders 2&3 never fire, regardless of which coil is plugged in (I have four to choose from)
New plugs, again.

TPS is still unplugged.

rleete 05-17-2014 10:02 PM

Sounds to me like some sort of bad connection.

hustler 05-18-2014 07:44 AM


Originally Posted by rleete (Post 1132119)
Sounds to me like some sort of bad connection.

Yet all test conditions indicate otherwise?

Reverant 05-18-2014 09:21 AM

At a loss here. Any locals with a 90-93 to test there?

hustler 05-18-2014 06:48 PM


Originally Posted by Reverant (Post 1132174)
At a loss here. Any locals with a 90-93 to test there?

Negative, too much unique stuff on my car. I'm trying to get my hands on a stim. Its very strange, plug 2 just barely burns a little when you look at the spark plug, #3 is totally clean. I can't get the engine hot enough to do a compression or leak test.

hustler 05-20-2014 03:11 PM

Okay, so when cold I have 120, 40, 30, 120 psi on a cmpression test in that order. with oil in the middle two that goes up to like 60psi. This is tested cold and #2 and #3 repeatedly had fuel wash-down when testing this stuff. Do I need to start looking at the engine for a problem? Would the plugs be ultra-clean and not burn at all if there were no compression?

This engine never drove like it was on two cylinders before this problem and the last lap it ran was the class record at ECR.

hustler 05-20-2014 03:32 PM

1 Attachment(s)
https://www.miataturbo.net/attachmen...ine=1400614321

curly 05-20-2014 03:47 PM

If you're sure you performed the compression test correctly on all four cylinders, WOT and 5 cranks, then your engine has a problem.

Edit: I wouldn't think fuel would lower the compression numbers by 75%, but I could be wrong. I've never had this issue and then performed a compression check.

hustler 05-20-2014 03:53 PM


Originally Posted by curly (Post 1132864)
If you're sure you performed the compression test correctly on all four cylinders, WOT and 5 cranks, then your engine has a problem.

Edit: I wouldn't think fuel would lower the compression numbers by 75%, but I could be wrong. I've never had this issue and then performed a compression check.

That's what we did. This engine basically has the same spark table as the white car did and that car had tens of thousands of miles on the tune and a couple track days. A Jim Stim in on the way for more computer testing.

Gt2560rMiata 05-20-2014 06:14 PM

Meh not an MS problem. Compression test speaks the truth time for a different motor

hustler 05-20-2014 10:03 PM

How many volts should I get on the coil trigger?

hustler 05-20-2014 10:04 PM


Originally Posted by Gt2560rMiata (Post 1132909)
Meh not an MS problem. Compression test speaks the truth time for a different motor

Even on a cold test that washed with fuel? I need to get a bore scope.

Wouldn't there be some burn even on dead cylinders, indicated on the spark plugs?

Gt2560rMiata 05-20-2014 10:25 PM

If you think its the rings being washed. Put an OZ of oil in each cly. Let it sit overnight, clear any oil still in the clys then retest compression


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