mechanical problems : diagnosis?

[teigan]

my track day was rained out, and while driving home, my '84 started to act up. the engine sputtered and lost power, although never stalling. seemed worse when the turbo gauge showed boost. giving throttle made the sputter worse, although very slowly throttling sometimes made it better. this condition was consistent on all gears, although neutral seems normal. anyway, the rain was violent, so i had the old thing towed home. tow truck driver claimed these cars weren't built for rain, and i'd taken on water. all i could say was, "the rain in spain falls mainly on england". anyone have a clue where i should start trouble shooting? thanks.

[fflyingdog]

I like your sense of humour.....about right as well ! Anyway your car ,sounds very much like a elctrical problem especially as when you try and load the engine the splutter gets worse ,i would get a can of trusty old WD40 pull all the leads and give them a good coating the stuff.I think that when you showed full boost the car wasnt being laboured which just in turn means that as you demanded extra fuel the plugs were not getting their full quota of energy to spark nice and fatly! hence maybe electrical plus it was peeing down,mine quite likes the rain but then again she has got used to it living on one of the English plains...Salisbury.
Regards
Nick S4s (slightly soggy)

[Dr.Hess]

Sort of sounds like ignition to me. Wet or weak. Dry it out and see how it does. Particularly around the dizzy, coil and leads.

Ad says:
"Never driven in rain."
Translation:
"Won't start when wet."

"Never driven in snow." - "Won't start when cold."

Dr.Hess

[igreenrover]

I'm currently enjoying some nice traditional British weather... if British cars weren’t built for the rain I’d be stuffed 300 days a year!

[greezmunky]

water in the part of the motor where the spark wires connect? should return to normal when it dries out

[teigan]

greezmunky may have sussed it. all the wiring and connections look solid. only questionable items were the rubber sparkplug boots. i'm assuming they should work even if the surrounding cavity fills with water. where does the rain enter , apart from the engine compartment cooling vent? on my vehicle the most obvious water comes up through the rear wheel wells, and into the boot. is there supposed to be a gasket or shield around the body openings for drainage tubes and electrical conduit? the carpeting soaks up any potential flooding, but hanging them out every night could be bothersome.

thanks for all the informative responses so far. can't imagine what these episodic inconveniences would be like without your moral support.

[lotusguy]

Hi,

All good suggestions so far. But, there are several other things that can produce similar effects such as those you're experiencing.

The first is to check the coil wire, this can work loose and cause the symptoms you describe.

Another is to be certain that the Turbo Diffuser shut-off is operating properly (USA Carb cars only). This shut-off is designed to prevent heat from the turbo from migrating to the carbs on shut-down to prevent vapor lock. This simple flap valve is operated via a vacuum actuator. It opens on receiving vacuum pressure to the vacuum actuator via an operating cam. Spring pressure closes the flap once the vacuum pressure is removed. If the vac actuator is leaking, the hose loose/off or the trunnion slipping on the actator rod, this flap will fail to open. Sufficient air leakage will allow the engine to idle just fine, but under load, the engine will bog down and die out as you describe.

Check all connections. You can even check the valve's operation by starting the engine and checking to see that it is open.

Happy Motoring !... Jim'85TE

[teigan]

the weather has relented! car drove normally this morning. thanks evryone for your help. my theory is the water is coming in from the naca intakes. sounds farfetched but it's testable with a spray bottle. i'll check all the other stuff jim mentioned this weekend. thanks lotusguy.

[DAVES_GT3]

hi
i have a problem on my 1997 gt3 . when i pull away it hesitates and judders as if it is being starved
of air or fuel. in any gear but only at bery low revs. say between
1500rpm and 2000rpm
any ideas?
dave

[ahmed303]

If you can use Corrosion X (www.corrosionx.com/) Instead of the WD40. I use it on the Airplane and the Lotus.

[lotusse89]

DAVES_GT3 said:

hi i have a problem on my 1997 gt3 . when i pull away it hesitates and judders as if it is being starved of air or fuel. in any gear but only at bery low revs. say between 1500rpm and 2000rpm any ideas? dave

Does it only do it when the car is cold?
If so, check your IAC step# using freescan, and adjust the minimum air rate bleed screw if necessary. If you don't know what I'm talking about, don't try and do it without freescan. I always forget the number but I think the IAC should be between 20-40 clicks let's say at idle when warm.

Travis
Vulcan Grey 89SE
www.lotuscolorado.com/vulcangrey

[deecee]

I had the same thing happen, under the same conditions.

Check the wires to your Fuel Pumps...I'd bet that the Protective Rubber Caps are off and the Rain is making a Ground.