3.9 efi running issues (hot wire)

Ok so thought best to start a new thread for the engine in my buggy now it's running.

I've checked timing which is about 6degrees btdc on idle with vac disconnected. I've checked air intake for leaks and fit a new filter. Checked all plugs are sparking with the timing gun.

1. When applying some throttle it almost dies before then revving fine though.

2. It doesn't sound right. Doesn't sound smooth and there is like a 'chuffing' noise (best way to describe) like a train. Chuff chuff chuff chuff like escaping air on idle, doesn't seem as bad on revving but still doesn't sound like a smooth v8.

My next step is to check what resistor is in the ecu loom as both o2 sensors on the exhaust are disconnected. It may be in a mode that does/doesn't require em.

It's worth noting that the previous owner has the distributor backward, the firing order is correct but the rotor arm on ht leads are 180 degrees out. Can't see that this would cause a problem but thought I'd mention it.

Any other suggestions would be really appreciated

After a bit of googling now I'm back indoors... it sounds exactly like this



So I'll order some gaskets and get them swapped. Could this cause the throttling issue?

No an exhaust gasket won't cause this.
A worn throttle position sensor would as they often don't respond just off idle. Easy to check with a multimeter.

Thanks cool, I'll google how to check for this. I'd planned to clean and check stepper Motor also

mordzy said:

It's worth noting that the previous owner has the distributor backward, the firing order is correct but the rotor arm on ht leads are 180 degrees out. Can't see that this would cause a problem but thought I'd mention it.

Click to expand...

I suppose it is possible. Would think very little adjustment as the vac and amp would be close up against the front cover, or your amp is not piggy mounted type

What I meant is that the rotor arm is in the wrong place on the compression stroke, it's pointing to two o'clock (looking at the engine from the front) however that electrode on the dizzy cap goes to piston 1. The following piston firing order on from that clockwise is correct to the manual.

Gotcha
You could remove and refit as per diagram.
As long as it works leave it alone.
I admire the style really, that's where it slotted on to the gears so that's number 1 now

Yeh that's what I thought. I hadn't planned to change it unless it had an adverse effect. I might look to set it as per the manual once it's all sorted.

I'm off in the garage now so will post up my findings on the tps later tonight. Thanks for the help cool

Ok. Tested the TPS. Negative probe to blue and positive to green. I get no voltage at all. So that must be goosed.

Here is a video. Also recorded for the lumpy running and noise to see if anyone can hear it. I can hear a exhaust chuff noise like it has a leak and something else under load?!



I then decided to check all the hoses to make sure they aren't blocked all seems fine till I came to the crank case breather. I removed this and saw a creamy sludge... I instantly thought head gasket but not sure is I know they can get messy with other stuff.

Appreciate any comments and help.

Could the crank breather pipe creamy stuff be something simple like condensation or is there too much for that?

When it is cold you'll be able to feel the exhaust gasses escaping without getting burnt. It sounds like one of the exhaust ports on the o.side head. Pennies to fix. Extract the bolts when they are warm or risk shearing one.
It does sound like the tps is giving no signal at all, not just a bit warn in the part throttle area.

Don't get too worried about the sludge unless there are other symptoms to worry about

I have some zorst manifold gaskets on the way so will swap them out. The sludge is a mm thick so could be condensation. Nothing under oil filter cap and dipstick is nice and translucent oil.

I've looked for that TPS online and no one has stock. It's the 1995 on model. ERR2263P is the after market number. Any suggestions where to get one for less than the price of a second hand engine with one in

mordzy said:

I have some zorst manifold gaskets on the way so will swap them out. The sludge is a mm thick so could be condensation. Nothing under oil filter cap and dipstick is nice and translucent oil.

I've looked for that TPS online and no one has stock. It's the 1995 on model. ERR2263P is the after market number. Any suggestions where to get one for less than the price of a second hand engine with one in

Click to expand...

Check and clean the plug socket wiring on the existing one, and disconnect battery while you do it for an ECU reset.

I had a similar exhaust chuff noise like it has a leak and something else under load, no quite as loud as yours but that my be down to your recording, however it was like a machine gun under load, with acceleration, going up hills, then it was found to be the manifold to Y pipe gasket had blown.
I drove for four months with that sound until my disco was in for service where the Y pipe has to be removed when replacing the auto box filter, so new replacement gasket were fitt on both sides. And so silence.

With the crankcase breather, clean it in petrol along with the pipe, although better to purchase a new breather and let the old one soak for a while and keep as a spare and reuse in the future when the new filter is due for a clean.

With the throttle pot. your looking to measure milli-volts not volts, is the meter your using up to that? It's something like 300mV

Thanks for the advice. Ill clean all connections tonight and re test. I may have had the meter in in the tens of volts settings by mistake. ill post back up tonight with my findings

Ok, bit of progress;

Started her up, felt exhaust manifold. Cylinder 2 & 4 are blowing pretty good so the gaskets are shot (should have some new to fit tomorrow). That probably explains the chuffing noise on the video

I removed the TPS and inspected the terminals. All seem clean and shiny.

I decided to test the engine without the TPS in to see if it made a difference to the stalling. And the fault has gone which is odd.

Is there anything I can do to test the TPS out of the engine? I've noticed that sticking the terminal from the meter up the back of the plug gets me no continuity to the terminal. Probably why I didn't get a reading. Is there any other way I can test with it connected without stripping some insulation?

mordzy said:

Ok, bit of progress;

Started her up, felt exhaust manifold. Cylinder 2 & 4 are blowing pretty good so the gaskets are shot (should have some new to fit tomorrow). That probably explains the chuffing noise on the video

I removed the TPS and inspected the terminals. All seem clean and shiny.

I decided to test the engine without the TPS in to see if it made a difference to the stalling. And the fault has gone which is odd.

Is there anything I can do to test the TPS out of the engine? I've noticed that sticking the terminal from the meter up the back of the plug gets me no continuity to the terminal. Probably why I didn't get a reading. Is there any other way I can test with it connected without stripping some insulation?

Click to expand...

Yes you could stab the probe through the insulation or clamp a scotch lock on. Even if the tps is broke, you will have the feed voltage. If not, the ECU may be at fault

mordzy said:

Ok, bit of progress;

Started her up, felt exhaust manifold. Cylinder 2 & 4 are blowing pretty good so the gaskets are shot (should have some new to fit tomorrow). That probably explains the chuffing noise on the video

I removed the TPS and inspected the terminals. All seem clean and shiny.

I decided to test the engine without the TPS in to see if it made a difference to the stalling. And the fault has gone which is odd.

Is there anything I can do to test the TPS out of the engine? I've noticed that sticking the terminal from the meter up the back of the plug gets me no continuity to the terminal. Probably why I didn't get a reading. Is there any other way I can test with it connected without stripping some insulation?

Click to expand...

Maybe have a read here:

https://www.landyzone.co.uk/posts/3584452/

You can check the throttle potentiometer off the car by reading resistance. The TPS is part of the idel control system, the ECU looks for the base voltage for a shut throttle and also looks at the engine speed and road speed inputs to know whether or not to turn on (or off) idle stabilisation. HTH.

Thanks guys. I'd previously read about the TPS being filed to allow for adjustment but also read contradictory info on the later models (mine) being self calibrating. I've managed to strip back the connector rather than cutting or scotch clipping and have some time this aft to test. I'll also be changing the exhaust manifold gaskets too so will have an update shortly