What injection system cleaners come recommended?

[NDavies4]

Have a rough idle when warm problem that I've been discussing on a US forum. One simple thing that was suggested to try out first was a fuel additive designed to clean out the fuel system and intake valves. In the US they seem to swear by Chevron's 'Techron' concentrate.

Did a Google search on UK sites but no joy in finding a supplier here. Does anyone know if it available in the UK, and if not what is a recommended alternative cleaner?

Regards

 

[Arnie]

Most well-known brands (Wynnes, STP etc) should be fine, but if you run the car with a quality, branded fuel, these detergents are usually part of the formula anyway.

(I have never found any of these injector cleaners to have made any improvements, but... no harm in trying)

I would also check you spark-plugs and the metal shields around the end of the cable plugs for shorts. Check for any signs of shorting or corrosion and also see if you hear a sharp clicking (from a spark to ground) on idle.

 

[mlc]

I have used both of the brands mentioned by Arnie with success in the past, although in a Ford. On each occasion the improvment came after the injectors had had chance to "soak" in the cleaner, that is add the cleaner, drive the car to get the additve through the system, let it stand for a few hours (over night if possible) and then any effect should be seen. I agree that good quality fuel will stop the problem in the first place.

Mark.

 

[NDavies4]

Read up a bit more on fuel system cleaners and the one I'm keenest to try is Red Line's SI-1 (or the smaller bottle called SI-2). Seems to be as highly recommended in the US as Techron, plus is available online in the UK.

'mcl', thanks for the soaking tip. Will give it a go.

'Arnie', thanks for your other suggestions which actually reminded me to try the following:
Got the car misbehaving nicely last night (very rough idle at the end of a 15min run after the car had been on the driveway for 3 days), so took the opportunity to try out a tip I read somewhere: Left the engine running; opened up the bonnet; took off the cover to the top of the leads/plugs; one at a time pulled off (then replaced) the plug leads and listens for any differences in the engine's idle. End result was that for 5 of the leads, the engine ran even rougher when they where 'popped' off, but for the other one (cylinder #1) it made no difference if it was connected or not. This I presume is quite significant and points to my problem being with the firing of this cylinder, so dizzy cap, lead, lead-end, plug and injector are the likely suspects?......

Note, leads have been replaced twice and plugs 3 times in last 2 years (10k miles) without improving anything so can assume they are not the problem. Have had the dizzy cap open and all looks ok, also no sign of shorting or corrosion in the metal shield at the end of the cable to cylinder #1. Most likely problem then the injector?

Will be interesting to see if the SI-1 cleaner improves things.... Will let you know.

 

[laurie.lea]

It does seem that your problem is more electrical than anything else. Back to your original question - I have read good reports in several magazines about a product called "Power Boost" - not a fuel additive but a foam that is squirted in the air intake whilst holding 2000RPM (Might need long arms or help from her indoors) Reports are all backed up by Dyno evidence and the magazines range fron Max Power to the Civil Service motoring association.
I am keen to try and wonder if anyone has any experience of this - particularly with diesels ?
The 25 pound price is a bit worrying though.

 

[markyce]

Hi,
I'm a bit late on the thread but.......
My W124 300Coupe was a bit lumpy on tickover even after a long run.

I tried Redex and after a couple of weeks and 2 tanks of gas it is now pretty smooth on tickover. I have been told that the big 12 valve sixes can be a bit lumpy anyway and after having plugs,leads and dizzy replaced was still a bit lumpy beofre using the Redex.

I also use their diesel additive for my C220 D.

 

[dieselman]

Read up a bit more on fuel system cleaners and the one I'm keenest to try is Red Line's SI-1 (or the smaller bottle called SI-2). Seems to be as highly recommended in the US as Techron, plus is available online in the UK.

'mcl', thanks for the soaking tip. Will give it a go.

'Arnie', thanks for your other suggestions which actually reminded me to try the following:
Got the car misbehaving nicely last night (very rough idle at the end of a 15min run after the car had been on the driveway for 3 days), so took the opportunity to try out a tip I read somewhere: Left the engine running; opened up the bonnet; took off the cover to the top of the leads/plugs; one at a time pulled off (then replaced) the plug leads and listens for any differences in the engine's idle. End result was that for 5 of the leads, the engine ran even rougher when they where 'popped' off, but for the other one (cylinder #1) it made no difference if it was connected or not. This I presume is quite significant and points to my problem being with the firing of this cylinder, so dizzy cap, lead, lead-end, plug and injector are the likely suspects?......

Note, leads have been replaced twice and plugs 3 times in last 2 years (10k miles) without improving anything so can assume they are not the problem. Have had the dizzy cap open and all looks ok, also no sign of shorting or corrosion in the metal shield at the end of the cable to cylinder #1. Most likely problem then the injector?

Will be interesting to see if the SI-1 cleaner improves things.... Will let you know.

I'd go fot the dizzy cap personaly. They can have hairline cracks and track either inside or to the metal shield.

 

[NDavies4]

Things looking up:

Used the Red Line SI-1 additive I mentioned: Put in 1/4 of the bottle (110ml) to a near empty tank, drove 5 miles or so then left car over-night to do 'mlc's soak trick. Next day added another 1/4 of bottle then topped up with 1/2 tank of Super UL (98 RON). Since then have driven the car hard (i.e. flooring it whenever possible).

After only 20 miles or so the car started to perform rather nicely - no more rough idle plus a very noticeable improvement in general acceleration responce and particularly kick-down.

Reading around, did find the following article on the net which seems to described my problem/solution perfectly:
http://brickboard.com/FAQ/700-900/Fuel_LubricantData.htm#NotesonCleaningUpFuelSystemDeposits

If car keeps runnnig well have promised it I'll fill up from time to time with BP 'Ultimate' or Shell 'Optimax', both of which I believe are 98 RON plus some other good additives which should help keep future injector deposits at bay.

After 2 years of suffering it's still early days, so haven't put the champers on ice just yet..... but so far so good

P.S. 'dieselman', thanks for the advise. A new dizzy cap is certainly #1 on the list if problem returns.