Fuel injection heat problem

[keith_h]

I have the Ford 2.0ltr efi DOHC engine from a GLS Sierra in my Roadster and returning from Stoneleigh I developed a loss of power with corresponding spluttering. If I eased back it would be OK for a while until it got even hotter. Another strange symptom was that the fuel guage , which is normally rock solid started to flick over about 1/4 of the scale. I turned on the heater to dump heat and that worked for a while (the fuel gauge settled down for a few miles then it all started again, plus the heat from the heater was so hot you couldn't hold your hand in front of it. When it first started it restricted my top speed to just under 70 but as the engine got hotter it slowly crept down over a distance of about 15 miles to a max of 30 and if I tried to accelerate it would splutter completely. The route home was to get off the motorway onto A roads, drive for about 10 15 miles, stop for a cup of tea and wait for the engine to cool down and then off we would go at a fair lick and repeat the process. It suggests a heat sensitive failing efi sensor or possibly a cable that is sitting against something extremely hot and eventually breaking through enough insulation to cause a breakdown.

Anyone else ever experienced the same or can suggest what to do to try and track it down. The car is perfect on tick over this a.m. ?

[Gareth]

Re: Fuel injection heat problem

With so much heat, you've got the name of the car right!

[lil_red_roadster]

Re: Fuel injection heat problem

Was the radiator hot..? Just wondering if the thermostat was stuck closed, forcing the ECU to lean-off the mixture and alter timing due to excessive heat buildup..? That could explain why the heater was so hot.

[peterboat]

Re: Fuel injection heat problem

Where is the air filter? on my 2.3 hunter it is behind the radiator last year it caused havoc [see the thread] anyway a new radiator and a shield for the air filter cured it this year I am going to move the air filter to get cold air to improve power and running

[David]

Re: Fuel injection heat problem

Was the radiator hot..? Just wondering if the thermostat was stuck closed, forcing the ECU to lean-off the mixture and alter timing due to excessive heat buildup..? That could explain why the heater was so hot.

Exactly this happened to me with similar symptoms last autumn. New thermostat fixed it.

[wiggiesworld]

Re: Fuel injection heat problem

With so much heat, you've got the name of the car right!

Only if you rename it a Marlin 'Roaster'.....

Interesting thread on a couple of points:
I've just replaced the MAF sensor for mine, running a 2.0 EFi Burton Tuned Pinto. What was happening with mine was the tickover from a cold start would hunt all over the place. Once it got warm it was fine. A new(er) MAF out of a 2L Transit (easier to find than a Sierra and it uses the same part number) has improved it no end. The MAF issues didn't cause any over heating or restricted flow issues like you describe. The MAF also sits behind the radiator so will get warm but this doesn't appear to affect it in normal running, certainly nothing like you describe.

I also updated to a new filter and as I also still have my filter behind the rad as described by peterboat, haven't noticed any issues with that though I can see there will be benefits in putting in a shield or re-positioning. Note to self for winter work.......

I'm inclined to agree with lil_red_roaster in that if your thermostat was stuck that there's no telling what effect excessive heat build-up would have on the MAF/ECU.

[dcunn]

Re: Fuel injection heat problem

I think this whole thing is just a plant - well done KH !

FWIW agree, check thermostat, certainly seemed & sounded OK when you started it before leaving (and before the engine warmed up)

[keith_h]

Re: Fuel injection heat problem

Thanks for all the input guys, I am off to buy a new thermostat tomorrow. I am going to try and get the old one out tonight and boil it to see if it is working. I am also going to send for some insulation so that I can make some protective heat shields for several sensors. I will let you know what transpires.

[greyV8pete]

Re: Fuel injection heat problem

I have had a couple of waxstat type of thermostats fail in the past. They do usually fail "closed" which would certainly account for your problem if you have that type. Peter.

[chris_cussen]

Re: Fuel injection heat problem

If you are try to get a new thermostat be careful, as there are two sizes and you can't tell from the engine number or donor car. They look identical! go to a motor factors and check the diameter of the replament. Off hand I seem to remember the difference is only a few mm, something like 78 vs 82mm (but don't quote me on the exact measurements)