CIS hard to start when warm

[evanwebb]

Hi all, looking for help here: my CIS basic ITC car is difficult to start when the engine is warm/hot. It takes a minute or more of cranking and then it slowly coughs to life. The fuel system seems to be fine but teh car doesn't have the stock fuel acculumator and I'm wondering if that is the problem. Or something else? thanks...

[Streetwise guy]

Ci cars are very very prone to starting issues with heat soak and residual pressure loss. If you don't have a check valve and accumulator to maintain pressure at the injectors, the fuel vaporizes. You are relying on fuel pressure to open the mechanical injector, and it takes forever to push enough liquid fuel through for it to run properly. It can be a bit of a bear to track down the leaks, as it can be back through the pump check valve, out the fuel distributor through the fuel return line, from the warm up regulator to the return line, or out the injector or cold start injector tips. A lack of accumulator only makes it worse, since you have a smaller volume of fuel to leak before the vapor problem rears its head.

Thats the bad news. Good news is that a fairly effective repair (or hack job, depending upon your opinion) is to add a pushbutton to actuate the cold start injector when you are cranking the car. On a race car, you could just replace the factory actuating wires with your own power and ground supply, but on customer pay jobs I used to leave the factory setup in place, and add a second ground wire through the pushbutton. The injector is supplied power from the starter bypass terminal on every start. It is grounded through a thermal timer, which is an electrical switch that is normally closed while cold, but opens when warmed from either engine heat , or from the current flowing through it while cranking. Piggyback a wire on the ground side, run it to a normally open pushbutton, and ground the other side of the button. Mount it on the opposite side of the steering column, so you can push it while cranking the engine. This should make it acceptible, at least.

Beware, my experience is with Volvo, so there may be subtle differences in wiring. The systems are substantially similar.

[John McFarland]

I had a switch wired in just like described. When the switch was flipped on, the cold injector would operate when the starter switch was activated. I never had start up problems again...

[evanwebb]

Thanks. I was planning to add a momentary switch for the cold start injector anyway so I'll go ahead an do that.

I didn't know there is supposed to be a check valve inside the fuel pump, is that really correct? I thought that's what the accumulator was doing. Would it be a benefit to just add a check or flapper valve in line between the fuel pump and the fuel distributor?

[pfcs]

The check valve is in the fuelpump fitting that the outlet banjo and acorn nut go over. The accumulator is teed into the supply line leading to the fuel distributor.
Everybody is correct in their suggestions, however I'd prefer to have a system that had an accumulator and didn't leak down outside spec. I would be concerned about the time I screwed up and fouled a plug on the false grid. The smaller accumulators are still available wholesale for around $65.
PS: a simple way to check system pressure and leakdown is to drill a 3/16 hoe thru a cold start banjo, countersink the small hole w/5/16, and braze a 2" stub of 5/16 (8mm) tubing into the hole. Substitute it in the 5th injector and stick a guage on it.
If you wanna watch control pressure, do the same w/smaller of 2 banjos @control press rgl.

[evanwebb]

Hi Phil, if you could point in the direction of a place that has the accumulator for $65 I'd appreciate it, I've seen more like $200. THanks.

[pfcs]

Evan-PN: VW 853 133 441// Bosch 0 438 170 042 for CIS-E A2, my cost $76.68 from Worldpac. I have a couple of rusty/OK used ones I'd give away if someone picked them up.
If you can get someone to pony-express it and pay cash I can get it for you for $80.
Regards, Phil

PS-upon posting I see your info-the CIS E accumulator is cheaper than the CIS-Lambda. It should work OK. There are several other accumulators available, depending on your want. There is a huge MB one w/single fuel fitting for 113.37 cost.
The 78 Scirrocco PN: 431 133 441B/0 438 170 019 list: $208.55, my cost 144.