Small cold start issue.

Hi all,

I'm trying to resolve a small cold start issue. In the mornings we have around 20 to 25 degC here. It takes around 6 or 7 seconds for the car to fire and needs a little press of the throttle. Once it fires up its a little rough and idles around 900rpm for around 3 minutes then it purrs and idles around 1000rpm.

I've tested the following:

1. Coolant thermistor resistance at the sensor and at the relevant ECU pins 2 and 21. Both read almost identical and are inline with the Graph that Steve Magnusson has posted.
2. Power to the red wire on the thermistor switch is fine.
3. Protection relay fuse is fine.
4. I've removed and checked all leads for resistance that they are all in spec.
5. Opened and checked the condition of the distributor contacts and rotor. Cleaned them up just in case.
6. Fuel pressure and all flow rates are in spec.
7. Cold start injectors dont fire but I'm assuming its because its not actually cold enough. I've read on another forum where Steve has stated above 68 deg F they don't fire and it runs open loop till its warm. The warm up regulators are also closed at this point.

I've double checked these:

1. Vacuum in both banks is perfectly aligned.
2. AFR is fluctuating during the warm up period and the Lambdas are swinging back and forth as they should until its warm and everything if much more steady.

Is there something else I can look into that I'm missing?

I just had a similar problem with my old Merc SL500 which has a similar system to our cars and we found that even though the protection relay was testing ok, once we replaced it the car was perfect and actually drove better than it has in 5 years. So wondering if I could have the same issue here. Although the relay cost of the one for the merc was only £15 new. LOL

 

even at home in summertime at about sometimes nearly 28°C the cold start valve gets power when starting. because the water temperature mostly is a little less after a night then the outside temperature.

normally those are a little open at this temperature

 

Our over night temperature outside is around 16 degC at the moment. The car is in an insulated garage so I'd doubt it gets lower than the 20degC. But I'll check if they get power. I only did the test where you remove them to see if fuel is coming out. Which it wasn't.

I'll double check again in the morning but when I tested them just after testing the throttle micro switch I'm sure they were fully closed but could be wrong.

Thanks.

 

I should also state that I've checked the throttle micro switch and at idle measuring the ohms at the ECU I get 1.5ohms and once the throttle opens I get 11,500ohms.

 

What year and type of TR? Kjet or KEJet? I also have a TR in Dubai (91 Euro spec, KEJet) and have had issues with cold start injectors.

 

Very possible IMO (but there are no WURs on a KE-Jet TR). One test you could do is connect the CN (orange-black) wire at the water thermoswitch on the LH side of the water Y-pipe to the R (red) wire (simulating a cold, closed water theroswitch) and see if that improves the cold start behavior. Don't leave it that way for a long time or if the water temp gets above about 150 deg F (and be careful to not ground the red wire as this will blow the Protection Relay fuse).

If it does help, you might confirm that the water thermoswitch will close when cold, but this is just a basic problem for KE-Jet TR in warm climates/garages.

 

Hi John, mine is also a KEjet Euro spec.

Hi Steve, I'll give this a try this weekend. The units I was refering to are the units under the plenium that connect from the fuel metering unit to the plenium next to the cold start injectors. I've realised now their called auxil

 

Very good, but I've gone back to refamiliarize myself with this system (rather than just using my flaky memory ) and I left something out -- the Thermo Time Switch (TTS). If connecting the two wires at the water thermoswitch together has no effect (you can also remove one wire from the water thermoswitch and measure the resistance between the two terminals to see if it closed = less than a few ohms or open = infinite ohms), remove the connector from the TTS and ground the RV (red-green) wire for the first couple seconds of starter motor cranking (simulates a cold closed TTS). Same sort of thing here -- when cold, the resistance from terminal on the TTS where the RV wire connects to ground should be just a few ohms or less, and when warm, the resistance from terminal on the TTS where the RV wire connects to ground should be infinite ohms. Finally wouldn't hurt to put/try a different ...113 relay in the relay U Starting injectors control relay position.

I'll add that there's a ton of wiring and connections in this CSI system so doing things like unplugging/replugging the round C12 and C13 connectors on the black box and the j white horizontal connector at the fuse/relay panel to wipe those connections wouldn't hurt, and if the locking rings on C12 and/or C13 are broken/missing = not a good thing for this CSI system.

 

Hi Steve do you know what the part number is for this? I took it out and the relay cover is badly cracked. But I cannot find a part number on it.

The cars temperature is around 34degC.
The water thermoswitch resistance between the two terminals was 0.45 ohms. With one wire disconnected.
The TTS resistance was 58 ohms. Between where the RV wire connects and ground. I tested it with various ground locations and got the same result.

The C12 and C13 have new locking rings. I've rechecked them and they are fine. I took all the white connectors out and checked them, they all seem fine. I also check the connectors under the coolant expansion tank and they were fine too.

 

Relay U is nothing special -- just a single pole 30A relay with terminals 30-85-86-87. Part numbers would be:
Ferrari 4013007 = Bosch 0332014113 (which is the stock metal-cased part but now obsolete and probably unobtainable)
Bosch 0332019151 (black plastic case)
Tyco V23234-C0001-X006 (brown plastic case)
But there are many other manufacturers like Standard Products, etc. Any auto parts store should have something appropriate. It is a bit strange that yours has failed as it not a relay that is always conveying a lot of current (and running "hot").

This good, and, if you make this same measurement when the engine is up to temperature, it should be infinite ohms. But one point here is these thermoswitches have hysteresis -- i.e., it matters what state they were in before at any ambient temperature between the switching points. For example, if the switch had gotten down to 25-30 deg C, and closed, it would remain closed until it got heated up to 63 deg C and opened -- so if you measured it at 40 deg C on the way up in temperature, it would measure closed. However, if it had been heated up to be above 63 deg and opened, as it cools down it would still be open at 40 deg C on the way down.

This is bad, and indicates that you need a new TTS. That resistance should either be infinite ohms (hot and open) or just a few ohms maximum (cold and closed). Ferrari and Bosch part numbers shown below (make sure you get the one for KE-Jet and not the K-Jet one):

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Thanks Steve. Was a bit surprised this morning when I seen they are $200 to $500 for used ones LOL
Cannot find a new one anywhere.

 

Are you searching using "Bosch 0280130219"?

https://www.autodoc.co.uk/bosch/668259

I believe it's used on Audi, VW, and maybe BMW so it shouldn't be total unobtanium.

And references like this can give you other automakers part numbers to look for and what vehicles they are used on:

https://niparts.com/Fac/E67CD6/BOSCH/0280130219.html

 

Yes searching for that part #. Already found the BMW cross reference #13621274631.

All the reasonably priced ones are not in stock. Like the autodoc link above.

 

go to a BMW dealer parts store, may be they have?
same TTS is in VW/AUDI 034906163, BENTLEY, PORSCHE and other cars from that time period

 

Hey Joe, not sure that VW part # is correct. When I search for it the photo is very different.

 

when I search from thailand in germany it shows the right item. but it looks a little different. important is the thread and the connectors. but those I can not see
may be you will find another better photo?

https://www.volkswagen-classic-parts.com/catalog/de_de/part/034906163?srsltid=AfmBOoqryuM0or5Bxn8CqMtW4yv6EXapRb7u_KIVblsDq8x-0u_rHJgx


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That "different" shape VW TTS matches the shape of the 118790 TTS that MCP now provides:

https://www.ferrariparts.co.uk/part/ferrari/118790

(but whether it is a KE-Jet or K-Jet version? = I don't know)

 

I've ordered the VW part as a few cross references including the ferrari parts site show the same numbers on the side. Even though they have tried to blur it out. So it arrives in about 8 days. Once I have it I'll report back if it's working so we have another alternative. It was $145 including shipping from the UK to Dubai. Which is around half the price of the BMW alternative.

 

what is the difference between those 2 TTS? temperature? seconds?

 

Yes, the time-temperature behaviors are different (see the graphs on the TR WSM pages mentioned later), but It's also the internal construction/wiring. The K-Jet TTS (see page D18 in the TR WSM) has two heating elements, and, when the switch contacts are open, there is still a path for current to flow in the W terminal path to ground. Whereas, the KE-Jet TTS (see page D81 in the TR WSM) has only one heating element, and, when the switch contacts are open, the W terminal is completely disconnected from ground.

 

thank you steve for explaining

 

Hi Gents,

The new sensor arrived today. Its fitted and tested it in the car at 3ohms when at around 30degC.

This is the old and new side by side.

The car did start better than before but still longer than it would usually take. I'll test it again in the morning as its much cooler here in the mornings now.