Throttle position sensor

[chrism]

It appears theat I've been very unfair on the TPS.

I've followed good advice and tested it with EScan - and all is fine.

It seems I might be suffering 'tractor-running' due to a different problem, initially thought to be vacuum hose but now identified as a possible f/injector fault since reading the LEC post of a pal who had the same cyls 1+3 breakdown with healthy sparks whilst tripping in France.

He took one of the offending f/inj caps off and motored home on 3 cyls - and mine fired up on 3 in the same way. They're wired in pairs and apparently if one fails it switches the other off...

But try getting a set of f/injs in UK.

And yes initially I made the error of buying Ultra-flow MSI31 injectors from the RAuto incorrectly labelled (over years I subsequently found...) catalogue. They're suitable for n/a m100s but incorrectly recommended for turbo ISUZU (but, curiously, not AWD - the ISUZU variant that has our turbo engine )

Anyway, I've just got a good used set (Delphi, 2ohms impedance and flow rate of 325cc @ 3bar) thanks to Steve in Essex, so I'll be able to report back with good news soon I hope

[chrism]

Yep, Steve's Delphi injectors were the missing piece of the jigsaw puzzle . T'stat, MAT sensor, fuel filter were 'done' beforehand whilst wrangling the 2-cyl 'conversion'... I measured their impedance and they all checked out at 2ohms, sprayed carb cleaner through them whilst 'clicking' the innards using a PP9 battery and she's purring along sweetly now, seeming to go a little more effortlessly

I haven't done an EScan nor have I disconnected the battery to reset the sensors, tho' I'd imagine that was done when the new fuel filter - another offering from RAuto that had to be replaced at the last minute cos it was listed for 'turbo' but threads didn't fit - was being replaced by David Rose Classics, a local 'magician'.

One of the top injector retaining clips needed straightening then subsequently broke. Try getting any of these, folks; they're more rare than the injectors that I couldn't find in the UK but Steve came to the rescue again and one of his spares fitted .

Finally when measuring the impedance of my old injectors all were 2ohms, apart from the failed one which was 1ohm - so using Steve's set of clean replacements in such good condition made sense

It strikes me that in the past we may have 'chucked' them when they were plentiful and we could easily get shiny new, but if anyone has one like in the attachment below - an original OEM Rochester/Delphi, I gather - that they could throw my way, I'd clean it up and have a set that'd be matched-by-make that a LEC pal could use in order to get them out of trouble (w/out throwing big money over the Pond for stuff claiming to be ISUZU turbo).



I was really over a barrel. I received what RAuto thought were the correct article and the only other used set that I'd found disappeared when sent to the wrong postcode... (All this time I was clogging up David's garage space.)

Loadsa stress over NLA m100 f/injectors If I can save a fellow LEC pal from this it'd be a good turn...

[KenS]

Its good new that you resolved the issue.
Injector issues seem to becoming more common.

I have a spare original injector that should be OK, it measures 2 Ohm and 'clicks', cannot be sure how good the spray pattern is, but happy to send it to make your spare set up to 4.

WIN_20261030_19_20_04_Pro.jpg

Its marked 9134 17089116. I guess your address is still the same - Little D..... I'll get it in the post Monday.

I was going to make a jig to pressurise and pulse spare injectors to see the spray pattern, run cleaner through and calibate their flow but thats another project still on the 'to do' list (because ! have another set of 4 injectors from my 'new' engine which had one sticky injector, replaced them with a set of 4 RC Engineering injectors with slightly higher flow last year).

[chrism]

Wow thanks; quick reply KenS. Yep we seems be experiencing a shortage of injectors atm

Your injector looks 'OEM' (slightly longer...) Has it got a single hole at the end like mine? No listings on mine - but your 2ohms + clicking sounds good...(Without sounding tarty I'm trying to get one that's exactly like the other 3 in the hope that it'll have the same reach between the rails and (much) the same spray pattern)

IF you post it (yep still Little D...) please include your a/c details so's I can pay back BUT it sounds like I ought to be sending you mine since you're going to refurb + calibrate etc. in a better way? That's above my skill set since I'll only be able to spray thru carb cleaner whilst cycling the mechanism.

However it works out, rather than 'chuck' or 'stash' it'd be good to be able to lend/offer a set to a LEC pal if one of us gets stuck over a barrel (as I very nearly did, but for the very welcome thoughtfulness and care of another LEC-er)

Again, happy to send any or all of mine your way if you prefer...

[muley]

Great point, thanks. I've taken out the MAT and the plastic part is a little loose. I can suck/blow air through it with difficulty but that shouldn't happen imo.

A new Delco part for GM cars is only £7.99 so I'm gonna replace it as a matter of course...I expect it'll test okay electrically but if there's a chance it's leaking...

Can I get away w/out a jiggle valve in the t'stat I wonder?

Regards the thermostat; probably yes. If you examine the t-stat closely there should be a v shaped slot where the valve seat works - this serves the same purpose i.e. air can flow permanently

[KenS]

Yes, I think the injector is the same type and with a 91 date code should be an original build part, it will be on its way Monday to make up a reserve set:

inj9.jpg

I am not yet ready to clean/calibrate injectors, hopefully I'll get something cobbled together in the next couple of weeks/months. Using a pressure brake bleeding tank that could contain paraffin or injector cleaner, hope it can hold a fairly steady pressure and use an Arduino and high current driver to pulse the injector, just got to make a 3d printed holder for the injector. Then collect the sprayed fluid over say 30 seconds in a measuring cylinder for comparison. I'll post how it goes when I have someting working.

pump.jpg