Forum » General Tuning Discussion » Haltech issue - 3000RPM Misfire/lean like 2 step

Haltech issue - 3000RPM Misfire/lean like 2 step

General Tuning Discussion

Discuss all things tuning in this section. News, products, problems and results. 

Page 1

So over the past 6 months i've had weird misfire issues ive changed the plugs, coils, leads and removed the injectors to inspect.

I've noticed some noise in my ecu like something has gone loose.

also I have attached some screenshots of the lean condition it works sort of like a 2 step but instead of rich very lean. When I dial out the timing -50% it goes away..

what has caused my timing issue? or ecu issue? it seems to drive mostly fine but there is some areas in the map where it run lean while on load upto 17afr boost is fine

haltech map pw - lexie

Attached Files

If you've got something loose rattling around inside your ECU I would start by finding out what that is and where it's come from. You need to sort this first and it may be worth sending the ECU back to Haltech for it to be inspected and tested to ensure you aren't chasing your tail with a hardware fault.

Is your misfire a new development or has it always done this since the ECU was installed/tuned?

Hi Andre,

I'm sending off the ecu to Haltech today since they are local. The misfire has occurred a few times in the past 6 months once on the highway on the way to work the spark would break up at cruising speed and made no power. I thought this was due to a bad batch of fuel and it didnt come back for months.

Once it came back at cold start so I Replaced the cam position sensor, coils,leads/plugs and removed the fuel injectors to inspect and modify the fuel rail for return system.

I have noticed that the lifetime Lexus Fuel pump strainer filter appears dirty so I have ordered a new sock from US. Changed fuel pump I can get it to idle as rich as I want but at that RPM range it seems to act funny so probably the ecu nothing else on the tune has changed.

I had to increase the VE to 60-70 where it used to be around 50 just to get rid of lean areas

It sounds more like a fuel delivery problem than a timing issue.

Have you tried monitoring your fuel pressure? I've been chasing a lot f new customers 'lean conditions' lately that have came down to dropping fuel pressure as a result of voltage at the fuel pump dropping. The attached picture had been to another shop 3 times, it was the fuel pump controller failing

Attached Files

i'll plug in a fpr over the weekend and do some testing

the fuel pump is wired directly from ecu 12v

the only other change is i removed the fuel pulsation damper with a banjo fitting

Hook up a volt meter to the fuel pump while you're actually driving and see what the voltage is - it should be 13.8-14.2 volts ideally.

Those fuel pulsation dampeners are actually quite an important component in many cars and removing them can cause some weird tuning problems. I can't say that is your issue but I've seen some dramatic fluctuations in AFR in our 350Z as a result of a faulty dampener.

The rattling noise appears to be the LED lights have fallen off the board and now rolling around

will try the suggestions thanks guys!

Ok changed the fuel pump sock/filter housing and re-installed factory fuel pulsation damper and did the trick for the most part.

I had to increase voltage of dead time 10% for safe rich condition off to re tune now

No more cut/lean out