My car failed MOT, bugger!

[Admin-bloke]

James, when was the last time you changed the oil?

I reckon you should change that and the filter, and get the engine hot before the retest

If the oil is old it will be contaminated and will cause high hcs, more so than the mixture.

Are you working this weekend?

Al

New spark plugs, air filter, oil change and fresh fuel will sort that out easily....

[jamesrguk]

James, when was the last time you changed the oil?

I reckon you should change that and the filter, and get the engine hot before the retest

If the oil is old it will be contaminated and will cause high hcs, more so than the mixture.

Are you working this weekend?

Al

Oil and filter changed about 2 weeks ago, air filter 2 months ago other bits (spark plugs, leads cap etc... ) about 2 years ago.

I know the mixture if fubar because if I have it set to run right at idle it runs like a bag of poo under load.

Nick set the CO. etc... at Eurotec last year, and got it to idle smooth as a silk, but the minute you started driving it was a complete nightmare, it kept stalling, stammering under acceleration etc...
The only thing I could do to get round the problem was to richen the mixture at idle, so it ran over rich at idle but fine under load.

Somthing is obviously wrong with the mixture enrichment system on the car, I know all the pressures were spot on when Nick tested them last year, but somthing is clearly not right.

I will dial down the old mixture screw and see if I can get it through.

Any idea on what I should be checking for a long term solution?

James

[Admin-bloke]

Did you get the matching venturi and fuel distributor in the end? Can't remember if you did but I can remember your fuel curve was way out and you had some different k-jet parts on.
Re-check your bosch codes again or put them on here.
Dan put a useful post on with bosch part numbers and what engines they came from.

I do have a volvo venturi but the fuel distributors I have both need overhauling.

See if you can get a known working complete K-Jet set from someone.
Ask Dan to see if he has any spare k-jet stuff. I might have a couple of spare injectors but I would have to dig them out.
You could weaken it to blag it through the MOT and at eurotec pull the injectors and do a spray pattern test into jam-jars.
This way you could do a basic check on spray pattern and fuel flow, dribbling injector etc.......

[DeLorean Cars]

Seems pretty clear cut that you need to run a higher primary pressure. IIRC you aren't running a Euro metering flap, but you are running a Renault 2.7-sourced euro metering head. All bets are off when it's mixed 'n' matched like that.

[arranj]

Here is Dan's post: viewtopic.php?f=24&t=486




My car sailed through this morning first time - don't mean to rub it in. Serious offer though if you're quick enough, I'm fairly sure I can pull some strings to get an MOT booked up here at short notice. He's open on Saturday too. I think it's a valid case to say that the garage of Caley Hall Car Park is one of the very few specialists that can repair a DeLorean MOT failure, and of course a pre-booked MOT will cement the case. http://www.nopenaltypoints.co.uk/NoMOTA ... lties.html

[jamesrguk]

It has correct larger venturi to match the FD, they came together straight off a running Volvo.

When Nick last looked at it it was all matched up correctly, Nick checked the fuel pressures, including the CPR and we upped the primary fuel pressure with one of Dans' shims and got the idle sweet as a nut and the CO etc... was good. But when I took it for a test drive it stammered and stalled constantly.

To get home from Eurotec I dialed up the mixture screw approx 1/2 turn clockwise, it smelt rich and hunted at idle but drove 99.9% fine.

I will have to check the CPR number and see if it's the right part no. I would think it's almost certainly a fuel related issue.

Any ideas?

James

[jamesrguk]

Seems pretty clear cut that you need to run a higher primary pressure. IIRC you aren't running a Euro metering flap, but you are running a Renault 2.7-sourced euro metering head. All bets are off when it's mixed 'n' matched like that.

- Primary pressure was tested and set to the correct specs
- The metering flap was changed about 3/4 years ago for the correct larger, volvo unit which I purchased complete with fuel distributor from a running volvo.

Are there any vacuum lines that could be wrong and preventing the correct enrichment?

I think I can bodge my way through the emissions, it's gone through fine for the last 3 years, and the emisions have been within requirements, but this was the 1st MOT since Eurotec 2009 when it was fiddled with.

J

[Admin-bloke]

It has correct larger venturi to match the FD, they came together straight off a running Volvo.

When Nick last looked at it it was all matched up correctly, Nick checked the fuel pressures, including the CPR and we upped the primary fuel pressure with one of Dans' shims and got the idle sweet as a nut and the CO etc... was good. But when I took it for a test drive it stammered and stalled constantly.

To get home from Eurotec I dialed up the mixture screw approx 1/2 turn clockwise, it smelt rich and hunted at idle but drove 99.9% fine.

I will have to check the CPR number and see if it's the right part no. I would think it's almost certainly a fuel related issue.

Any ideas?

James

I have seen a car stammering (pre-ignition) due to one of the bob weights' springs in the spark distributor coming off causing too much advance early on. A timing test of revs vs advance with vac advance disconnected would rule this out.
Another cause I have seen is the fuel pipes on the fuel distributor not being correct between cpr and fuel distributor, but that was on an oem delorean one with frequency valve.
I am assuming that there is no issue with HT lead breakdown anywhere.
I am assuming there are no vacuum /air leaks.
I am also assuming that the fuel distributor and injectors are working ok. Test would be as said before with injectors in coffee jars for basic spray pattern/ flow rate check per injector/ fuel distributor outlet.

[jamesrguk]

I have seen a car stammering (pre-ignition) due to one of the bob weights' springs in the spark distributor coming off causing too much advance early on. A timing test of revs vs advance with vac advance disconnected would rule this out.
Another cause I have seen is the fuel pipes on the fuel distributor not being correct between cpr and fuel distributor, but that was on an oem delorean one with frequency valve.
I am assuming that there is no issue with HT lead breakdown anywhere.
I am assuming there are no vacuum /air leaks.
I am also assuming that the fuel distributor and injectors are working ok. Test would be as said before with injectors in coffee jars for basic spray pattern/ flow rate check per injector/ fuel distributor outlet.

These problems occur when the car has warmed up so I need to establish all the things that alter when the temperature rises and that may point me in the right direction?

I need to do a complete check of everything so I know where I stand, firstly so that I know all of the components I have on there are correct to work together.

But if you look at my videos on YouTube those were all done with the car in it's current set-up so I can't beleive that I am running the wrong components.

If I can squeeze the old girl through the MOT next week then obviously I'll bring it to Eurotec, I'm actually more worried about it failing on the Hand brake, I'm going to tighten that up further on Sunday so it's got some chance of passing on the Wednesday.

J

[Admin-bloke]

The tests will take no time at all and seeing as i am bringing my test gear up, the checks can be re-done and noted down as a test sheet. This way hopefully it can all be sorted.

I will try and remember to bring my spare injectors.
My car is at work so I am trying to pack it as I go along.