2001 SWB Colorado 3.0 Diesel - Intermittent Power Loss

[Highway_Star]

I am about to inherit a 2001 Colorado. it's the 3l intercooled common rail diesel.

It was my late dad's car, he bought it new and my mum has driven it since he died 7 years ago.

It's been a damned good car, very few issues. Rusty rear lights, drivers seat collapsed years ago and the passenger door mirror does odd things in the rain were about it. Until recently....

Ever since a tank of Tesco diesel it has occasionally had a hiccup. Starts no problem and revs freely off load. On load can be a different story.

It'll pull away then sometimes around 2500 rpm just runs out of steam. Hold your foot on the floor and it will maintain speed but not accelerate, and occasionally surge and take off like a scalded cat.

The engine management warning light has been on and off.

it has the odd day where it's perfect, but this has become more prevalent now so my mum has ordered a Rav4 to replace it, and passed the LC on to me.

Thus far it's had fuel biocide treatment (don't think that made any odds), fuel injection cleaner (this made some improvement), fuel filter replaced with genuine item (the EM light has not been on since) and also a spray of 10K boost EGR cleaner (again this made some improvement).

Next on the list to look at are the pick up from the tank (is there a pump in the tank?), and the fuel lines themselves.

I've read a lot on the interweb about suction control valves, so I'll give those a clean and replace turned through 180 degrees.

 

[Shayne]

I don't think there's many on here who have the same specific truck HS but as far as I can tell everything but the engine is identical to the earlier 1kz . I've never had any problems with my older truck but iirc there are 3 filters built into the fuel pump (if indeed it's the same pump, there's a great vid on YouTube about servicing it ) . There is a filter in the fuel tank that has caused others problems . And replacing the rubber pipes at the tank seems a fairly common practice . I will have a look at the pumps tomorrow if they are the same you could turn up the fuel a little to see if that helps .

 

[Bob]

I had this exact issue a while back... Changed the filter, bllew out the fuel lines and checked the electrical connections on the throttle body. Not sure which one it was, but 3000 miles later and no sign of any problems. Never had the EM light on though

 

[Shayne]

Not the same pump . Lots of evil electrickery on these though so might be worth pulling all the plugs looking for a corroded connection ?

 

[Iwan]

Just a word of warning. ... dont pull the plugs out with the ignition on or the engine running cause the ecu could lock you out. They're quite sensitive to change in the circuitry and the immobiliser will activate just like mine did when I was extracting the ecu wiring for my lj70 conversion. ..
Have you had a diagnosis on the circuit s ?

 

[Highway_Star]

I'm pretty well versed with electronics, I'll be careful. I know this car has a Thatcham 2 security system, it locked me out when changing the batteries once.

My local friendly garage plugged a scanner in and it gave a code about the mass AFM. But he wasn't 100% trusting it as he feels it could be red herring. ie that the airflow doesn't match what the ECU thinks it should be, therefore the AFM is faulty. Kev's thinking is more like "the air flow isn't what the ECU thinks it should be because the engine isn't producing power under load".

I'm tempted to get a Techstream off Ebay and reset the codes, then drive it with the laptop live until it happens again.

It's not fundamentally broken, because when it works it pulls like a train. No smoke, no knocking, starts easily. It just feels like you've taken your foot off the gas. Hence I'm investigating fuel issues first.

 

[Shayne]

I'm out of my league here but might a leaking injector seal throw up the same fault codes ?

I read somewhere that toyota dealt with this problem by stating the seals MUST be replaced whenever the injectors are checked during normal servicing .

 

[wobbly]

Does it have a potentiometer on the acc pedal ?

 

[Highway_Star]

Short answer is "probably". I haven't seen a Bowden cable to the injection pump.

 

[Beau]

It does sound like either a fuel related issue, or fauly maf sensor....

Unplug the MAF sensor and see if the truck runs any different. If it stays the same, there's your problem. If it changes the behavior then it's not the problem. It does sound fuel related with everything you've secribed so far. Dropping the tank and checking the pickup line would be the next check I think...

 

[Highway_Star]

Agreed Beau,

It's been 'cured' in the past by a couple of doses of fuel system cleaner additive. This time it's improved but not cured. And when it's in a good mode, it goes really well.

Thankfully the weather is improving so I'm more keen to crawl around underneath. Really hoping there is an access panel as the tank is 1/2 full at the minute. That's going to be messy/heavy.

Good point on the MAF, I've done that very thing with my Range Rover to (dis)prove it was playing up. In that instance disconnecting put the RaRo into LIMP and made it run a lot worse, turned out to be the advance/retard mech in the dizzy was freewheeling .

I'm actually quite looking forward to playing with this car. Our experience with Toyotas has always been that they are reliable and when things do go wrong you can find a definite reason.

 

[Bob]

There's an access panel under the carpet in the back, it's the top of the float for the fuel gauge. You should be able to see down if there's any crud in there.

Are you using genuine filters or aftermarket. I think the Toyota ones are a bit finer and let less through to the pump.

I tried the throttle body, EGR, intake pipe on the pump, tank everything... I'm pretty certain it was fuel delivery at the filter housing.

 

[Highway_Star]

Now on a genuine filter, the one I removed was Blueprint.

Time and mucky fingers will tell.

 

[Highway_Star]

Diagnostic cable arrived on Friday, I had to ressurect an old laptop as it's much easier to get working under XP.

That's done, didn't have time to go up to mum's where the LC lives presently, so plugged it into the wife's Corolla. It works! Techstream gives out a plethora of information, most of which may not be relevant but time will tell.

My plan is to check and clean the strainers in the tank. Then clear the codes and observe.
If no better, replace fuel lines. Clear codes and observe
Then the inspect, clean and rotate the SCVs.

 

[Highway_Star]

So I got 10 minutes today to plug the laptop in.

Returned a code, 28(8) Fuel Pump Systems Failure (short).

This is before any checks on fuel lines etc. Reading around the web it would appear that this means the ECU thinks there is a discrepancy between what the fuel pressure should be and what it actually is. That fits with it being a fuel delivery issue, somewhere along the line.

Interestingly, Techstream reports that there's a cruise control ECU there and happy. Yet the car doesn't have cruise control fitted. Or maybe it does, just the switches aren't there on the UK version?

 

[Highway_Star]

I had a look at these SCVs and came to the conclusion that Techstream is telling the truth.

The books says to pull the connector off and measure the resistance of the SCV, should be between 1.5 and 1.7 Ohms at 20ºC.

These were reading 1.2.

Suction Control valves are waiting for me at the Post Office, I'll pick them up and fit tomorrow.

 

[Highway_Star]

Behold the cause of the problem.

These are the 'Suction Control Valves'. £168 delivered.

Took me longer to chat to a mate and have a brew than to actually change them.

I removed the air filter housing lower section to facilitate access, quite straightforward once that's out of the way.

The Colarado now sounds much happier, no hesitation and pulls like it should do.

 

[Yorkshire4x4]

So I got 10 minutes today to plug the laptop in.

Returned a code, 28(8) Fuel Pump Systems Failure (short).

This is before any checks on fuel lines etc. Reading around the web it would appear that this means the ECU thinks there is a discrepancy between what the fuel pressure should be and what it actually is. That fits with it being a fuel delivery issue, somewhere along the line.

Interestingly, Techstream reports that there's a cruise control ECU there and happy. Yet the car doesn't have cruise control fitted. Or maybe it does, just the switches aren't there on the UK version?

Highway star can you please advise I am having simmillar issues to your fuel problem but mine judders when I turn the key. I have ordered scv valves fro. Roughtrax they will arrive today. I am thinking of buying the cable you bought on Amazon if the scv doesn't resolve the issue. Are these cables plug and play my mechanics diagnostic machine didn't show up any faults.
Thanks

 

[macker1965]

Hi Lads
new here. I have an issue with my j90.
When cold she drives normally. after she gets hot and i want to get more power she goes into limp mode.
Must admit even though i paid for it my fuel filer had black crap in it. i replaced it myself. Still the same issue.
Dumped the fuel tack and cleans filter in the sender unit. still no difference.
put another new filter on and still the same.
Cleaned carbs on her and still the same.
Now i have code p1226> fuel line malfunction. she is registering 15% with no foot on pedal and 72% when foot to the floor.
Also have a P1520 code stop light switch circuit.

Please Help!!! love the j90 and dont want to change her
Tony Mac

 

[Shayne]

"Cleaned carbs" is yours a petrol 90 ?