Yet Another bogging/slow/not running correctly 1fz (1 Viewer)

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Joined
May 23, 2013
Threads
21
Messages
148
Location
Australia
This is my 1fz,

2E51B7AA-669B-4907-BA4B-F5A41D901C43.jpeg


Pretty sweet hey,
Except it runs like a dog,


1993, manual, aus spec 80
Got it on the road ran beautifully for a few weeks, until the start of this week when I noticed it bogging accelerating from the traffic lights at the end of my street.

I’d describe it like a carby car when cold, you put your foot down and the motor noise increases but it doesn’t really go faster and occasionally jerks as it comes up in rpm.
Feels like it’s worst at 1000 - 2500rpm
Problem is way less severe when warm but still feels like it’s lost a fair few ponies.

Its done 400,000km, what ever that is in freedom units,
I was expecting filter or pump as it lacks the ignition break down noises I’m used to when one of these kill a set of leads or plugs.

I’ve thrown a new pump and filter at it - no change
Confirmed the flappy maf is triggering the fuel pump
Bypassed fuel pump resistor - no change
Bypassed the entire fuel pump control circuit and relay - no change

Fresh 98 fuel and injector cleaner.
Pulled plugs, none are wet look a little lean but nothing really stood out.

Yesterday it felt like the ecu really struggled to maintain a idle, would slowly drop become increasingly choppy until about 150rpm, almost stall then go back up to 1100rpm and repeat.
I haven’t experienced this again.

Being an Australian car it has no EGR so the harness doesn’t get cooked, I have had a good visual look at the rest of the harness and it looks ok, even near the knock sensors.

Also no engine codes with the terminals jumpered.

They never come with cats here so nothing to collapse.

The intake tube isn’t cracked.

I’m just about to dive into checking sensors and such with a multimeter.

Is there anywhere I should start? Also what’s the probability of the fuel reg dying? The reg vacuum port filter is clean and not blocked.

I’m also very tempted to cut my losses already and put a haltech in it.
 
whats with the air filter housing being moved from the original position? Where is it getting air into the filter as the original intake port at the DS fender is open?
Sounds like it may be starving for air
 
The disconnected tube is the under wing air pick supply, not being connected should not affect performance.

I would try spraying a little lubricant around the induction tubing, do it while moving the tubing about, also look for disconnected or holes in the vacuum lines.

Surging at idle is often indicative of an air leak, even from the brake vacuum servo or booster as some call it.

Regards

Dave
 
whats with the air filter housing being moved from the original position? Where is it getting air into the filter as the original intake port at the DS fender is open?
Sounds like it may be starving for air
The disconnected tube is the under wing air pick supply, not being connected should not affect performance.

I would try spraying a little lubricant around the induction tubing, do it while moving the tubing about, also look for disconnected or holes in the vacuum lines.

Surging at idle is often indicative of an air leak, even from the brake vacuum servo or booster as some call it.

Regards

Dave


Air filter has been moved for coil over towers, it sucks just out of the engine bay now,

I have confirmed no cracks on the intake piping, the air filter is clean, one breather hose was cracked I have replaced it,
No other air leaks I have found,

It also hasn’t done the surging at idle thing again, but still runs like a dog.

I tested the maf by the fsm with a multimeter, tested out ok, has anyone had one faulty while still testing ok?

I think I’ve got a fuel pressure reg somewhere I’ll swap it out and see what that does I guess
 
Stupid dumb maf was at fault

$50 for another and its fixed
Go buy more MAFs and sell to those in the USA for a huge mark-up.

Cannot find them in USA. Check the part number to see if they are the same as yours either no cats, etc.
 

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