Lexusgs430: Points towards a weak engine, in my perception. Do a compression test on all your cylinders.

dsunmade: I drive a manual 1998 Toyota Avensis, 1.8 liter petrol engine. Anytime I top up or fill up the ac coolant and drive, it drags the engine. The acceleration slows significantly and I often have to switch off the AC while attempting some race car maneuvers. Is this normal or is it a symptom of an underlying problem? Thanks for your candid, well-informed advice.

ZIM DRILL:


Is your AC aftermarket or the original from manufacturer ?

Ikenna351:

This should have been the first question in this matter.

Ikenna.

dsunmade: I drive a manual 1998 Toyota Avensis, 1.8 liter petrol engine. [b]Anytime I top up or fill up the ac coolant and drive, it drags the engine. [/b]The acceleration slows significantly and I often have to switch off the AC while attempting some race car maneuvers. Is this normal or is it a symptom of an underlying problem? Thanks for your candid, well-informed advice.

au.hanson:


If its not factory fitted, expect the dragging effect with a 1.8 litre engine, else check your performances components and clean them up or replace the bad ones. Anyways, that's a topic for another day

Trac: Compressor systems take an average of 12kW (16 horsepower). It is a factored design consideration and should not be noticed during operation. Engine - to begin with - is at poor state of health. A tune-up is needed. It could be anything (a simple task that mayn't take a minute to a job that takes a few hours). That is why there is appreciable-loss in performance during operation. Have a mechanic diagnose it. The root-cause(s) is what he will discover and take necessary measures to remediate it.

IdaraCHODB:

He needs a mechanic that is educated, not someone who knows how to fix a car but does not know the theory of how cars work or failing that someone who will listen to him as he suggests what to do based on the information provided here

9icetoo: Okay, so heres my two cents. I have read somewhere on this thread that efi systems have something called a compensator on them that comes on when an extra load like an ac is put on the engine. This compensator works with the maf i suppose. Supposing your maf isnt really telling the ecu the truth, this compensator might not work properly hence the drag on your engine. In my recent post i wrote about my recent tuneup which involved cleaning out my maf and air cleaner. Guess what, it worked a treat by treating this same symptom u r complaining of. Since ur ac is stock, i believe ur engine should be able to handle its load without a noticeable drop in power. try cleaning ur maf, throttle body and air cleaner. It just might work.

dsunmade: That's my problem. Where to get someone who really knows how cars work and not some technician who doesn't know the underlying principles of what he does.

Ikenna351: Op,

Your engine is not dragging, it's hesitating, I think.

Since the AC is factory fitted, it's now ruled out.

I don't know the state of your engine combustion chambers, neither do I know the state of the car engine injection system. You didn't tell us if you have scanned the car and the results. You didn't tell us how often you top up the engine oil or it doesn't consume oil. You didn't tell us what colour of smoke emits from the exhaust or no colour at all. You didn't tell us the state of the ignition system, in this case, I mean the spark plugs. The issue you are experiencing may have nothing to do with the AC, but the state of the engine, ignition or injection system of the car. When load like AC is placed on the engine with faulty system(s), it will give out similar symptom you are experiencing.

Get an electronic contact cleaner, methylated spirit, alcohol or any good solvent aside carb cleaner. Get a toothbrush as well, new or used. Disconnect the battery terminals, if you want to. Then start pulling out, spraying and brushing all wiring connectors in the engine bay you can lay your eyes on, with the solvent and toothbrush. Pull out the connector, spray in the solvent, brush the pins, spray in solvent again to flush out dirts, allow to dry and plug back, both male and femalr connectors. Don't forget to clean the engine ECU connector as well. But please, don't spray the solvent on the ECU pins where you unplugged the connector. Brush the ECU pins with dry brush and clean only the connector. Sometimes, when a injection components connectors corrodes, it would disrupt the the ECU receiving complete signals or values from the sensors/components the connectors are connected to. The ECU may manage to run the engine with such incomplete info from the sensors, but as soon heavy load is added or placed on the engine, the power will drop.

I don't know if your engine has IAC; I don't know if its more pronounced while engine is at idle; even though the symptom sounds unlikely to be an IAC issue, but it wouldn't hurt to clean the IAC (Idle Air Control valve) with carb cleaner, allow to dry, lubricate and mount back. Usually IAC will make rpm drop at idle when clogged or even stall the car when deaccelerating, especially when AC is on.

I wouldn't rule out the ignition, the spark plugs until am sure. If you have not replaced those spark plugs since you got the car with recommended one and not knowing when it was last replaced by the previous owner, it's time for you to replace them, with the electrode properly gapped. I mean properly gapped, not according to the spark plug manufacturer, but your car manufacturer for that engine.

It could still be your AC system, but I don't have much to say on this, if that is the case.

I can't think of any other thing for now. Maybe others will have more or better suggestions to add.

Ikenna.

ziccoit: ^^^ @Trac, if you don't live in Nigeria; you would not understand how difficult some things are. In a whole state you may not find a single qualify mechanic/auto technician that knows his job.
Look, some things are just unavailable and there is nothing you could do about that. In this case, would you stop using cars because the environment is not enabling? Nigeria is unlike UK or USA where good mechanics abound. Here, they are so scarce especially outside the big cities (Lagos, Port, Abuja)

dsunmade:
_{Thanks. I replaced the plugs with OEM manual prescribed plugs about 2 months ago after gapping them and noticed an improvement in the working of the vehicle. The car doesn't consume oil.} The smoke is usually colorless but occasionally white on revving.

Trac:

While what you have stated is fact, another consideration is if the poster is willing to pay the higher price associated for guaranteed service. This is the problem I have gotten to observe repeatedly from nairalanders and Nigerians in real-world. Nigerians are always for the bargain. So, they cling to Nigerian mechanics and get all services at unfair bargains. I mean perpertually. The mechanic - on the other hand - is shrunk; for profit has been marginalised and often motivated to be fair and not be optimum.

Theories of how cars work can only be attained via the discipline of Mechanical Engineering or it's specific derivatives. It is deeper than what many can dedicate to. Many that work on cars don't have this. It will be unfair to expect this of the larger percentage of Nigerian mechanics. The ones with such (scientific) background charge a lot of money for their services because they guarantee their work. Nigerians tend to avoid those. They'd rather get the result of the diagnosis and opt to carry out the repairs at their own convenience.



What's stated might mitigate the symptom (effect). It is not a root-solution. The one to whom the vehicle will be given to carry out diagnoses will comprehensively "detail" the vehicle for root-cause-effects and root-cause-failures. In engineering, faults are never resolved from effects (symptoms as thread implies) and then worked upon. You end with a system that is categorised as "undependable." In systems, all problems (always) are tree-like. It is called the "fault-tree" (or deductive) and an investigation into what effects have been conjured is a fault-tree diagnosis (or deductive-diagnosis). This is a reflection to the logic that problems are always tree-like. The objective is for the root-cause/s, so that failures are completely eliminated (eradicated to prevent future occurrences) and possible preventions made. As aforestated, it requires understanding and it is always comprehensive. Sometimes, fate could have an effect to be an isolated issue; thus a surface problem with no faulty associated dependencies. Nevertheless, proper investigation is never usurped because this fact comes as conclusion after all deductions have been made. A car serviced occasionally outside of this standard approach is a "partially-functional" vehicle (no matter how well it rides). This is because there will be several unresolved root-issues that are subservient to normal vehicle operation; till ultimate failure occurs.



On scale, a basic repair is needed. It's not a big issue; although you omitted to state other effects that you are experiencing. One note of caution to you: don't go cheap. Get a reputable person and pay the cost associated for the proper workmanship. You should also get a guarantee for the service done. A good mechanic will not propose revisions (part revisions) that are questionable. If failed Toyota parts are identified, the same should be fitted in replacement or a genuine revision. Doing otherwise will be a tradeoff from dependability in favour of uncertainty. Logic will bear me witness.

IdaraCHODB:


Just reading this response.

I noticed that you were both thorough and methodical in your writeup above, makes me realize you have got stuff upstairs!

You have a point.

Pay to play!

I recently had to "ferry" a mechanic 500km across Nigeria to fix my car so I could return home, so totally identify with the sentiments expressed above!