After years of searching, I’ve finally obtained my car (‘81, manual, grey interior). Overall I think it’s in good shape and the previous owner kept it well maintained. Unfortunately I have little information on the service history and it appears to have the original style fuel lines in the engine bay. Unsure if these are the actual 41 year old lines or if they’ve been replaced at some point, but I’ve decided not to risk it and replace them with the modern stainless kit.
I know there are already some excellent posts here on this topic, and I’ve read through as many as I could find in order to prepare for the job, which I decided to attempt myself using the DPI lines, bolts, and injector holder kit.
At this point in the process I have all 13 new lines installed, DPI injector holders, new bolts & washers, new fuel filter, everything torqued to spec. After performing several rounds of pressure testing (RPM relay only, no start), I have some troublesome, very persistent leaks. I’m hoping some of you that have done this job successfully might have advice on what to try next, as I’m running out of ideas.
Here’s what I’ve done so far…
The leaks are occurring:
Main line to the fuel distributor (FD) (significant leak)
Cold start valve (CSV) to FD (minor leak)
One (probably both) lines to the pressure regulator (WUR) (moderate leaks)
Unfortunately the fuel filter appears to be leaking somewhere as well, but I’ll deal with that later.
So for the first round of pressure testing, I torqued the banjo bolts to minimum, tested, then max spec., tested. Leaking everywhere mentioned.
My assumption is that once crush washers have been torqued to max spec., they shouldn't be reused, please correct me if wrong. Can these be annealed with a blow torch? (Have never worked with this type of system before).
For the second round, I removed the bolts and replaced both top/bottom crush washers. Unfortunately the DPI kit provided no spares (seriously?), so I sourced an assortment of replacement metric washers on eBay. I eyeballed them for flatness and scratches; some were pretty bad, picked the best ones. Also made sure the fuel line end “eyes” were oriented parallel with the surfaces without requiring twisting on the lines. Ensured the correct number of washers were used, none stuck together.
Torqued to min, then max spec., still leaking. The WUR was leaking quite badly this time, and I believe it due to the fact that my eBay washers were a bit too large in outer diameter to properly fit into the recesses on the WUR.
For the third round, I tried sanding surfaces. I realize I could be making things much worse here if not very careful; don’t want to sand unevenly and round things over, create a low spots, or introduce radial scratches in the surfaces. Used the technique of poking a hole in the sandpaper, pushing the bolt through with a crush washer behind the paper to apply even surface pressure, while spinning the bolt in place. Cut a bit of the old fuel line to help apply even pressure, see pictures. Used 1000 grit paper.
Replaced (again) with new top/bottom washers, and torqued to min, then max spec, and managed to stop only the CSV leak. The others remain.
So at this point, I’m kind of at a loss on next steps. I have ordered a few sets of $$$ crush washers from Delorean.com directly for my next test; maybe my eBay washers are indeed trash. I can either continue trying the same things that so far have not worked, or I’m at the point of pushing past the torque specifications on these and see what happens. I’ve already (accidentally) over torqued one of the M8 bolts on the injectors and sheered it right off, so I know first hand how fragile these things are.
Before I do that, I wanted to see if anyone had any opinions on something else to try? Is there some type of chemical sealant I can use to help? Haven't even gotten to testing the injectors yet. Did not expect the job to be this tough, is this a typical experience with squashing leaks, am I just being impatient?
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