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P1800 DJet cold start issues

volvorod85

New member
Joined
Feb 21, 2003
Location
Sunny Socal
72 p1800 the whooe fuel system has been gone through. The car runs great, but Its hard to start cold. Car is a virgin, 72k miles, dealer not broken on the map sensor. Been though everything. All the connectors are clean, coolant and air temp and tps check out perfectly, fuel pressure 32 psi. Cold start injector was bad so it was replaced along with the thermotime switch but from a 240. The original is NOW. It's hooked up correctly no doubt there but with the injector unplugged I get voltage on both pins even though one is grounded without the starter wire hooked up to 12v. I wanna be sure I'm not missing anything and that I should be good with the 240s time switch. Any thoughts? I feel like I'm missing something stupid
 
Is the 240 thermal timer new? If not, it may be bad.

Did you wire it correctly? The G terminal goes to the starter.

If you want the correct thermal timer, I have them new and tested used.
 
Are your thermal timers the space type from the p1800 or the 240 type?

I ohmed it out. One terminal was 0 ohms the other was 25 ohms. Pretty obvious at that point the 25ohms is the heater in the switch and that I wired to the starter. Other one goes straight to the injector for its ground. Its a brand new VDO for a 240. I mean I don't think the timer size of it should matter for the b20 vs the b21, cis vs djet. That cold start injector should make a fire hose of fuel and it should light up pretry quick. I'm gonna double check the connector at the starter and the Injector. It's gotta be something stupid. It's a 70k mile car, I've gone thorough almost everything mechanical and as I'm doing the shakedown I'm finding all kindsa electrical things stuck and twitchy. Headlights didn't come on 2 times...relay or the switch, seat belt light flickers when the belt is unbuckled, panel lamp rheostat is finicky as are the door switches.

I gotta check the CO also. I bumped the adjustment on the ECU 4 clicks rich. Seems to me happier that way, just gotta get it to start in the normal 3 to 4 seconds instead of 10 to 15 of wanting to start and being funky.
 
I have the original style timers with the large and small blade connectors.

Have you tried to test the cold start injector directly by applying 12 volts? The pintle could be stuck if the injector hasn't been used in a long time.
 
The fuel system was replaced, literally (fuel cooling suspension etc etc)...tank cleaned and sealed, all new rubber lined, injectors sent out and serviced. The original cold start injector was toast and I think it cooked the old time switch. So replaced with a 'rebuilt' injector, it clicks, but i havent taken it out to see if its spraying haha, ill do that, it clicks loudly when 12v is applied so I doubt its stuck.
 
If it's clicking, it's probably working.

The thermal timer gets it's ground through the body of the part. Make sure it's not insulated somehow.
 
Pull the cold start injector out and have it spray into a fairly deep container covered with a rag (atomized gasoline spraying all over the place is bad news). While you crank the engine have somebody observe and time the spray (to confirm that the thermal timer isn't flakey). Observation is the definitive way to confirm that the injector is 'really working' rather than just 'should be working'.

Of relevance, is your fuel pump going through the priming cycle (about 2 seconds of operation) prior to start-up during key on, no cranking? This establishes fuel pressure prior to start-up. Once you start cranking the motor the fuel pump should start up again; but, the priming cycle establishes pressure before cranking which helps speed start up. In theory, the check valve on the pump should hold fuel pressure in the fuel system on engine shut down; but, ageing D jets with worn check valves, FPRs and maybe leaky injectors typical lose static fuel pressure pretty quickly when the pump is not running.
 
It holds pressure, that was the first thing I tested when I got the car running with the cleaned tank and all new parts because I wanted to verify fuel pressure was good and that it help pressure as the pump is original, haha our minds are on the same track, and yes it holds pressure like it should, the pump primes when the key is cycled on and starts soon as you crank it and runs for a second or so after cranking...

So, here is a new one and may more so be related the the issue...as I drive this car more things are popping up after its 17 year slumber. It wouldnt start, no spark...BUT a few times after i let go of the key when it would start, it would start running, like it was loosing ignition in the crank position. Now this has a pertonix in it and an original coil. Whats interesting it it runs fine, no ignition break down at all. But all the sudden no spark while cranking, then if it catches right there is spark.. I doubt the coil is failing, its possible and ill ohm it out. Also the petronix, ive seem em work or not work, not fail like this. And it happened after the car sat for 6 hours, then again after driving it for 15 minutes. So I need to hopefully get it to fail again and check the fuse block for power when cranking. Im hoping this is related to the cold start issue.

The headlight dimmer relay seems to be acting up, sometimes the headlights wouldn't come on, but after a flip of the dimmer switch they came on, so I need to pull it apart and look at the points in it. Door switches are sticking, fasten belt light flickers if you rock the seat belt reciever. Its all to be expected after 45 years and minimal mileage and 17 years of sitting haha. Thing is I did a quick search for an ignition switch, doesnt seem to be so easy to find.
 
Check your ignition switch (the electrical switch mounted on the back of the ignition lock cylinder). The ignition switch supplies +12v to the coil in both run and the crank key positions. It almost sounds like sometimes the coil is not getting +12v in the crank position and as soon as you return the key to the run position 12 v is applied to the coil and the engine starts. This is a fairly common problem associated with a dirty or worn ignition switch (and the flip problem where the car starts in the crank position; but, dies when you return to the run position).

I have a 142 E so I don't have the 1800 wiring diagram. You need to go here to get a copy of the 1800 wiring diagram if you don't have it already.

http://volvo1800pictures.com/sweden/Volvo_1800_dokumentation_main_page_en.php

From the wiring diagram, you will be able to find the contact off of the ignition switch which supplies the ignition coil. Disconnect the starter solenoid connection (you don't need to be cranking the hell out of your starter while doing this test!) and then check to make sure that you are getting 12v on that contact in both the run and crank positions. Since this appears to be an intermittent problem, try wiggling the key and moving it back and forth between run and crank to see if you can initiate failure of the switch. On my 140, new switches are available and not that expensive. Since the 1800 is more popular and typically has more reproduction parts than the 140, I would have thought replacement ignition switches would have been a no brainer. However, if the switch is similar to the 140 switch, you can open up the switch by bending back a couple of metal retaining tabs on the metal cover (watch for parts springing / dropping out). This gives you access to the switch contacts and sometimes you can fix the problem up by cleaning the contacts and applying a little of that Oxgard grease.

If you search on the internet, I seem to recall seeing a post by someone who took their 1800 ignition switch apart and rehabilitated it. I think it was on an British Volvo forum.

I rehabilitated my 142 E after a close to 35 year storage. Bad electrical connections were a huge issue. I went through every electrical connection cleaning and tightening up loose spade connections and lug/stud connections and checking the condition of the wires. Since you have a D jet, be aware that the insulation on the wires where they enter the termination plugs on the 4 fuel injectors, the throttle position switch, the engine coolant sensor and the intake air temperature sensor tends to harden, crumble and fall off. On the temp sensors this can lead to the controller reading incorrect resistance values which may not kill the engine; but, will cause poor operation. New or reproduction D jet connector plugs and the rubber boots are available if you need to re-do or re- terminate the plugs although they are kind of pricey.

Sometimes spray contact cleaners available from electronics suppliers can help improve the operation of a switch. I have found that the improvement tends to be temporary as the cleaners are really just degreasers and not effective at removing oxides on the contact surfaces. Best solution for rehabilitation is contact cleaner followed by burnishing the contacts and Oxgard on the contacts.

As a final note, your non starting when cold may be related to the ignition switch. The D jet gets its start signal off the coil + connection. If the coil is not getting +12v from the switch the D jet will also be dead.
 
Well got it to fail at the shop and it has 12v when cranking. I double checked the power at the main relay also. Found the petronix was dropping out when cranking sometimes. I'm guessing the failing coil may have had something to do with it. 4.3 ohms on the primary and 11k on the secondary. New bosch blue coil and new petronix and it fires up mich easier now. Replaces a bunch of the spades on things like the coil and the headlight dimmer relay and went through the rest of the stuff that's popped up over the weekend. The boss took it home finally tonight so ill find out tomarrow if i have my cold start issue fixed. Only thing that really sucks now is the trans is leaking pretty bad from the top down. The cover gasket is bad or the shifter seal..something and I'm too busy to deal with it so I gotta sublet it. All in all the car performs great long as no more gremlins pop up haha
 
It's usually the shift shaft seal that leaks, but the bushings can be bad also. The forward bushing that holds the seal is available, but the rear one was never available separately and has to be fabricated.

I have the forward bushing and seal in stock and there's a machine shop 2 doors down that can make the rear bushing.
 
Pertronix is kind of ****. I honestly prefer points, 75 breaker-less setup if it works/dist not worn out (no D-jet trigger points on 4cyl cars tho I think), or 123 dist if you/the customer has the $$$.
 
Yeah the shift shaft seal looks like its leaking..But you gotta drop the trans to do it so far as I know, and I just dont have the time nor do the power that be want me spending more time on the car. Im the resident electrical guy and ive got 3 harnesses waiting to be made and im doing a prototype harness for our broncos (i work for Icon). This was a nice step away from all that noise haha. And when the trans is out being a virgin its check and most likely replace the clutch and related parts, and reseal the overdrive and the whole trans for that matter, and go though the OD as well. Its the mushroom factor. If it was my car eh no brainer, its a long 1 day job...but its not haha.

Its the bosses car and the pertonix work fine. Ive had them fail yeah, they dont like a coil thats more or less than 1.5-3 ohms and they dont like the key being left on for extended periods of time.

Anyway...The cold start issue I have a theory. I 'rebuilt' the aux air valve with a new wax pellet insert from that one guy that sells them. I also removed the vacuum to the vacuum retard. The combo of these things make it want to idle close to 3 grand when warming up, so I stuffed a vacuum nipple in the aux air hose to choke it down a bit, now it idles at around 2-2100k when warminig up, I think thats still too high. When cranking it it will crank for 4 seconds or so, then wants to fire then keep cranking. I think its too lean from that aux air valve allowing too much air. Im gonna put a smaller vacuum nipple in the hose and choke it down more so i can get it to idle around 1500 or so and see what happens, but I think that will be the sweet spot. Ill post back when I know whats going on, I hate open ended threads haha.
 
Oh, it's your bosses car. That explains this blurb from the brochure.

With the ICON Reformers, take the same concept of modern
engineering hiding under vintage bodies, yet this time we restore
the vehicle to as new, concours condition. Rolling works of art.
Breathtaking. A 1950?s Mercedes? Or a 1930?s Packard phaeton...
Perhaps a 1941 Hudson pick up, or a Volvo ES Sport Wagon? It?s up to
you, your imagination, and our creativity

If he wants to sublet the transmission work, I'm available. I've got over 30 years experience rebuilding Volvo RWD manual transmissions. I have a large inventory of used parts should a hard part need to be replaced. All bearings, synchros and gaskets necessary to rebuild an M41 are in stock.

With his connections, your boss might be able to get Volvo George Swift to rebuild it for him, but he may not have access to used parts like I do.

Did I mention I'm relatively local?
 
The AAV was frozen completely so a quick internet search said there are none left...but you can get a kit to fix it from this guy. Basically heat it get the insert out and put it back together with a new insert. It works now but with no vacuum retard hooked up it revs faster cause the timing is where it should be...so I have to put a smaller orifice in the air hose to bring the fast idle down lower. The car just runs better with out the vacuum hooked up and the timing curve is dead on woth just the mechanical advance so im gonna leave it.
 
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Well I got a smaller orifice in the air valve hose and it fired right up, idled at 1100 rpm...Gonna try and go a little bigger, get it closer to 1500 when its cold. I feel like when it starts proper 2 times im in the clear haha
 
Sounds like the AAV is not closing all the way. Rebuild is good but they need to be adjusted by moving the inner sleeve and/or squeezing the bulb. Did you take it completely apart to clean and smooth the bores? Hence the suggestion about testing in hot water and freezer. The internal slide with the office needs to be fully closed at 160 F. If not you?ll get Air through the slide resulting in the high idle when warm. Putting a smaller office in the hose is simply defeating the slide purpose.

I have a picture but not allowed to post it.
 
I replaced the bulb and the piston inside moved smoothly. The bulb i took out has an internal adjustment with a screw, the replacement does not. It works fine, wide open when cold and closed at around 160 like it should be. There are 2 issues, the lack of vacuum retard, this would reduce RPM by quite a bit, and the rest would be with the adjustment on the screw on the bulb that is no longer there with the replacement. The orifice worked perfectly, car starts right up when cold and idles up, and drops just like it should as it heats up. No issues.

I say its fixed. Took a little playing with the orifice in the AAV hose, but aside from that it fires right up, idle comes up and slowly drops as it heats up. No adjustment and too much air from the AAV was seemingly causing the hard start in the morning
 
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